diff --git a/README.md b/README.md
index f5a72e8..5fd0fd0 100644
--- a/README.md
+++ b/README.md
@@ -337,9 +337,8 @@ and the debugger will print this:
 
 ```javascript
 source code:
---> var fib=func(x)
-    {
-        if(x<2) return x;
+--> var fib = func(x) {
+        if (x<2) return x;
         return fib(x-1)+fib(x-2);
     }
     for(var i=0;i<31;i+=1)
@@ -347,16 +346,16 @@ source code:
 
 
 next bytecode:
-    0x000848     4a 00 00 01     callfv  0x1(std/lib.nas:427)
-    0x000849     3d 00 00 00     pop     0x0(std/lib.nas:427)
-    0x00084a     07 00 00 00     pnil    0x0(std/lib.nas:423)
-    0x00084b     56 00 00 00     ret     0x0(std/lib.nas:423)
-    0x00084c     03 00 00 5e     loadg   0x5e(std/lib.nas:423)
---> 0x00084d     0b 00 08 51     newf    0x851(test/fib.nas:1)
-    0x00084e     02 00 00 03     intl    0x3(test/fib.nas:1)
-    0x00084f     0d 00 00 08     para    0x8 (x)(test/fib.nas:1)
+    0x0003a8    07:00 00 00 00 00 00 00 00     pnil    0x0 (std/lib.nas:413)
+    0x0003a9    56:00 00 00 00 00 00 00 00     ret     0x0 (std/lib.nas:413)
+    0x0003aa    03:00 00 00 00 00 00 00 56     loadg   0x56 (std/lib.nas:413)
+--> 0x0003ab    0b:00 00 00 00 00 00 03 af     newf    0x3af (test/fib.nas:1)
+    0x0003ac    02:00 00 00 00 00 00 00 03     intl    0x3 (test/fib.nas:1)
+    0x0003ad    0d:00 00 00 00 00 00 00 22     para    0x22 (x) (test/fib.nas:1)
+    0x0003ae    3e:00 00 00 00 00 00 03 be     jmp     0x3be (test/fib.nas:1)
+    0x0003af    45:00 00 00 00 00 00 00 01     calll   0x1 (test/fib.nas:2)
 
-stack (0x55ccd0a1b9d0, limit 10, total 0)
+vm stack (0x7fca7e9f1010, limit 16, total 0)
 >>
 ```
 
@@ -371,9 +370,8 @@ This will help you debugging or learning how the vm works:
 
 ```javascript
 source code:
-    var fib=func(x)
-    {
--->     if(x<2) return x;
+    var fib = func(x) {
+-->     if (x<2) return x;
         return fib(x-1)+fib(x-2);
     }
     for(var i=0;i<31;i+=1)
@@ -381,24 +379,24 @@ source code:
 
 
 next bytecode:
-    0x000850     3e 00 08 60     jmp     0x860(test/fib.nas:1)
---> 0x000851     45 00 00 01     calll   0x1(test/fib.nas:3)
-    0x000852     39 00 00 07     lessc   0x7 (2)(test/fib.nas:3)
-    0x000853     40 00 08 56     jf      0x856(test/fib.nas:3)
-    0x000854     45 00 00 01     calll   0x1(test/fib.nas:3)
-    0x000855     56 00 00 00     ret     0x0(test/fib.nas:3)
-    0x000856     44 00 00 5f     callg   0x5f(test/fib.nas:4)
-    0x000857     45 00 00 01     calll   0x1(test/fib.nas:4)
+    0x0003a8    07:00 00 00 00 00 00 00 00     pnil    0x0 (std/lib.nas:413)
+    0x0003a9    56:00 00 00 00 00 00 00 00     ret     0x0 (std/lib.nas:413)
+    0x0003aa    03:00 00 00 00 00 00 00 56     loadg   0x56 (std/lib.nas:413)
+    0x0003ab    0b:00 00 00 00 00 00 03 af     newf    0x3af (test/fib.nas:1)
+    0x0003ac    02:00 00 00 00 00 00 00 03     intl    0x3 (test/fib.nas:1)
+    0x0003ad    0d:00 00 00 00 00 00 00 22     para    0x22 (x) (test/fib.nas:1)
+    0x0003ae    3e:00 00 00 00 00 00 03 be     jmp     0x3be (test/fib.nas:1)
+--> 0x0003af    45:00 00 00 00 00 00 00 01     calll   0x1 (test/fib.nas:2)
 
-stack (0x55ccd0a1b9d0, limit 10, total 8)
-  0x000007    | pc   | 0x869
+vm stack (0x7fca7e9f1010, limit 16, total 8)
+  0x000007    | pc   | 0x3c7
   0x000006    | addr | 0x0
   0x000005    | nil  |
   0x000004    | nil  |
   0x000003    | num  | 0
   0x000002    | nil  |
   0x000001    | nil  |
-  0x000000    | func | <0x55ccd0a58fa0> entry:0x487
+  0x000000    | func | <0x5573f66ef5f0> func(elems...) {..}
 >>
 ```
 
diff --git a/doc/README_zh.md b/doc/README_zh.md
index 2f655e9..77f6480 100644
--- a/doc/README_zh.md
+++ b/doc/README_zh.md
@@ -322,9 +322,8 @@ local (0x55dcb5b43190 <+7>)
 
 ```javascript
 source code:
---> var fib=func(x)
-    {
-        if(x<2) return x;
+--> var fib = func(x) {
+        if (x<2) return x;
         return fib(x-1)+fib(x-2);
     }
     for(var i=0;i<31;i+=1)
@@ -332,16 +331,16 @@ source code:
 
 
 next bytecode:
-    0x000848     4a 00 00 01     callfv  0x1(std/lib.nas:427)
-    0x000849     3d 00 00 00     pop     0x0(std/lib.nas:427)
-    0x00084a     07 00 00 00     pnil    0x0(std/lib.nas:423)
-    0x00084b     56 00 00 00     ret     0x0(std/lib.nas:423)
-    0x00084c     03 00 00 5e     loadg   0x5e(std/lib.nas:423)
---> 0x00084d     0b 00 08 51     newf    0x851(test/fib.nas:1)
-    0x00084e     02 00 00 03     intl    0x3(test/fib.nas:1)
-    0x00084f     0d 00 00 08     para    0x8 (x)(test/fib.nas:1)
+    0x0003a8    07:00 00 00 00 00 00 00 00     pnil    0x0 (std/lib.nas:413)
+    0x0003a9    56:00 00 00 00 00 00 00 00     ret     0x0 (std/lib.nas:413)
+    0x0003aa    03:00 00 00 00 00 00 00 56     loadg   0x56 (std/lib.nas:413)
+--> 0x0003ab    0b:00 00 00 00 00 00 03 af     newf    0x3af (test/fib.nas:1)
+    0x0003ac    02:00 00 00 00 00 00 00 03     intl    0x3 (test/fib.nas:1)
+    0x0003ad    0d:00 00 00 00 00 00 00 22     para    0x22 (x) (test/fib.nas:1)
+    0x0003ae    3e:00 00 00 00 00 00 03 be     jmp     0x3be (test/fib.nas:1)
+    0x0003af    45:00 00 00 00 00 00 00 01     calll   0x1 (test/fib.nas:2)
 
-stack (0x55ccd0a1b9d0, limit 10, total 0)
+vm stack (0x7fca7e9f1010, limit 16, total 0)
 >>
 ```
 
@@ -356,9 +355,8 @@ stack (0x55ccd0a1b9d0, limit 10, total 0)
 
 ```javascript
 source code:
-    var fib=func(x)
-    {
--->     if(x<2) return x;
+    var fib = func(x) {
+-->     if (x<2) return x;
         return fib(x-1)+fib(x-2);
     }
     for(var i=0;i<31;i+=1)
@@ -366,24 +364,24 @@ source code:
 
 
 next bytecode:
-    0x000850     3e 00 08 60     jmp     0x860(test/fib.nas:1)
---> 0x000851     45 00 00 01     calll   0x1(test/fib.nas:3)
-    0x000852     39 00 00 07     lessc   0x7 (2)(test/fib.nas:3)
-    0x000853     40 00 08 56     jf      0x856(test/fib.nas:3)
-    0x000854     45 00 00 01     calll   0x1(test/fib.nas:3)
-    0x000855     56 00 00 00     ret     0x0(test/fib.nas:3)
-    0x000856     44 00 00 5f     callg   0x5f(test/fib.nas:4)
-    0x000857     45 00 00 01     calll   0x1(test/fib.nas:4)
+    0x0003a8    07:00 00 00 00 00 00 00 00     pnil    0x0 (std/lib.nas:413)
+    0x0003a9    56:00 00 00 00 00 00 00 00     ret     0x0 (std/lib.nas:413)
+    0x0003aa    03:00 00 00 00 00 00 00 56     loadg   0x56 (std/lib.nas:413)
+    0x0003ab    0b:00 00 00 00 00 00 03 af     newf    0x3af (test/fib.nas:1)
+    0x0003ac    02:00 00 00 00 00 00 00 03     intl    0x3 (test/fib.nas:1)
+    0x0003ad    0d:00 00 00 00 00 00 00 22     para    0x22 (x) (test/fib.nas:1)
+    0x0003ae    3e:00 00 00 00 00 00 03 be     jmp     0x3be (test/fib.nas:1)
+--> 0x0003af    45:00 00 00 00 00 00 00 01     calll   0x1 (test/fib.nas:2)
 
-stack (0x55ccd0a1b9d0, limit 10, total 8)
-  0x000007    | pc   | 0x869
+vm stack (0x7fca7e9f1010, limit 16, total 8)
+  0x000007    | pc   | 0x3c7
   0x000006    | addr | 0x0
   0x000005    | nil  |
   0x000004    | nil  |
   0x000003    | num  | 0
   0x000002    | nil  |
   0x000001    | nil  |
-  0x000000    | func | <0x55ccd0a58fa0> entry:0x487
+  0x000000    | func | <0x5573f66ef5f0> func(elems...) {..}
 >>
 ```
 
diff --git a/std/runtime.nas b/std/runtime.nas
index b6edeaf..bad3203 100644
--- a/std/runtime.nas
+++ b/std/runtime.nas
@@ -1,13 +1,29 @@
-# runtime.nas
-# 2023 by ValKmjolnir
-# runtime gives us some functions that we could manage it manually.
-
-# command line arguments
-var argv = func() {
-    return globals.arg;
-}
-
-var gc = {
-    extend: func(type) {return __gcextd;},
-    info: func() {return __gcinfo;}
-};
+# runtime.nas
+# 2023 by ValKmjolnir
+# runtime gives us some functions that we could manage it manually.
+
+# command line arguments
+var argv = func() {
+    return globals.arg;
+}
+
+var _gc_extend = func(type) {
+    return __gcextd;
+}
+
+var gc = {
+    extend: func(type, times = 1) {
+        if (times<=0) {
+            return nil;
+        }
+        if (times>16) {
+            times = 16;
+        }
+
+        for(var i = 0; i<times; i+=1) {
+            _gc_extend(type);
+        }
+        return nil;
+    },
+    info: func() {return __gcinfo;}
+};
diff --git a/test/console3D.nas b/test/console3D.nas
index 7c137b3..f4a2afa 100644
--- a/test/console3D.nas
+++ b/test/console3D.nas
@@ -1,252 +1,250 @@
-# ray tracing example
-# modified from Artem Yashin's project Console3D
-
-# MIT License
-# Copyright (c) 2021 Artem Yashin
-
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-
-# The above copyright notice and this permission notice shall be included in all
-# copies or substantial portions of the Software.
-
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-# SOFTWARE.
-use module.libmat;
-use std.runtime;
-use std.math;
-
-func() {
-    # allocate more spaces
-    for(var i = 0; i<10; i+=1) {
-        runtime.gc.extend("str");
-        runtime.gc.extend("vec");
-    }
-}();
-
-var (max,min,sqrt,sin,cos,abs)=(
-    math.max,
-    math.min,
-    math.sqrt,
-    math.sin,
-    math.cos,
-    math.abs
-);
-
-var (vec2,vec3)=(
-    libmat.vec2.new,
-    libmat.vec3.new
-);
-
-var (vec2add,vec2sub,vec2mul,vec2div,vec2len)=(
-    libmat.vec2.add,
-    libmat.vec2.sub,
-    libmat.vec2.mul,
-    libmat.vec2.div,
-    libmat.vec2.len
-);
-
-var (vec3add,vec3sub,vec3mul,vec3div,vec3neg,vec3norm,vec3len,vec3dot)=(
-    libmat.vec3.add,
-    libmat.vec3.sub,
-    libmat.vec3.mul,
-    libmat.vec3.div,
-    libmat.vec3.neg,
-    libmat.vec3.norm,
-    libmat.vec3.len,
-    libmat.vec3.dot
-);
-
-var (rotateX,rotateY,rotateZ)=(
-    libmat.vec3.rx,
-    libmat.vec3.ry,
-    libmat.vec3.rz,
-);
-
-var use_raw = func() {
-    vec2 = func(x,y) {return [x,y];}
-    vec2add = func(v1,v2) {return [v1[0]+v2[0],v1[1]+v2[1]];}
-    vec2sub = func(v1,v2) {return [v1[0]-v2[0],v1[1]-v2[1]];}
-    vec2mul = func(v1,v2) {return [v1[0]*v2[0],v1[1]*v2[1]];}
-    vec2div = func(v1,v2) {return [v1[0]/v2[0],v1[1]/v2[1]];}
-    vec3 = func(x,y,z) {return [x,y,z];}
-    vec3add = func(v1,v2) {return [v1[0]+v2[0],v1[1]+v2[1],v1[2]+v2[2]];}
-    vec3sub = func(v1,v2) {return [v1[0]-v2[0],v1[1]-v2[1],v1[2]-v2[2]];}
-    vec3mul = func(v1,v2) {return [v1[0]*v2[0],v1[1]*v2[1],v1[2]*v2[2]];}
-    vec3div = func(v1,v2) {return [v1[0]/v2[0],v1[1]/v2[1],v1[2]/v2[2]];}
-    vec3neg = func(v) {return [-v[0],-v[1],-v[2]];}
-    vec2len = func(v) {var (x,y)=(v[0],v[1]); return sqrt(x*x+y*y);}
-    vec3len = func(v) {var (x,y,z)=(v[0],v[1],v[2]); return sqrt(x*x+y*y+z*z);}
-    vec3norm = func(v) {var t=vec3len(v); return vec3div(v,[t,t,t]);}
-    vec3dot = func(a,b) {return a[0]*b[0]+a[1]*b[1]+a[2]*b[2];}
-    rotateX = func(a,angle) {return [a[0],a[2]*sin(angle)+a[1]*cos(angle),a[2]*cos(angle)-a[1]*sin(angle)];}
-    rotateY = func(a,angle) {return [a[0]*cos(angle)-a[2]*sin(angle),a[1],a[0]*sin(angle)+a[2]*cos(angle)];}
-    rotateZ = func(a,angle) {return [a[0]*cos(angle)-a[1]*sin(angle),a[0]*sin(angle)+a[1]*cos(angle),a[2]];}
-}
-
-var clamp = func(value,_min,_max) {
-    return max(min(value,_max),_min);
-}
-var sign = func(a) {
-    return (0<a)-(a<0);
-}
-var step = func(edge,x) {
-    return x>edge;
-}
-
-var vec3abs = func(v) {
-    return [abs(v[0]),abs(v[1]),abs(v[2])];
-}
-var vec3sign = func(v) {
-    return [sign(v[0]),sign(v[1]),sign(v[2])];
-}
-var vec3step = func(edge,v) {
-    return [step(edge[0],v[0]),step(edge[1],v[1]),step(edge[2],v[2])];
-}
-var vec3reflect = func(rd,n) {
-    var d=vec3dot(n,rd);
-    return vec3sub(rd,vec3mul(n,vec3mul([2,2,2],[d,d,d])));
-}
-
-var sphere = func(ro,rd,r) {
-    var b=vec3dot(ro,rd);
-    var c=vec3dot(ro,ro)-r*r;
-    var h=b*b-c;
-    if (h<0.0) return [-1.0,-1.0];
-    h=sqrt(h);
-    return [-b-h,-b+h];
-}
-
-var box = func(ro,rd,boxSize,outNormal) {
-    var m=vec3div([1.0,1.0,1.0],rd);
-    var n=vec3mul(m,ro);
-    var k=vec3mul(vec3abs(m),boxSize);
-    var t1=vec3sub(vec3neg(n),k);
-    var t2=vec3add(vec3neg(n),k);
-    var tN=max(max(t1[0],t1[1]),t1[2]);
-    var tF=min(min(t2[0],t2[1]),t2[2]);
-    if (tN>tF or tF<0.0) return [-1.0,-1.0];
-    var yzx=[t1[1],t1[2],t1[0]];
-    var zxy=[t1[2],t1[0],t1[1]];
-    var tmp=vec3mul(vec3mul(vec3neg(vec3sign(rd)), vec3step(yzx,t1)),vec3step(zxy,t1));
-    outNormal[0]=tmp[0];
-    outNormal[1]=tmp[1];
-    outNormal[2]=tmp[2];
-    return [tN, tF];
-}
-
-var plane = func(ro,rd,p,w) {
-    return -(vec3dot(ro,p)+w)/vec3dot(rd,p);
-}
-
-var main = func(frame) {
-
-    var height=15*2;
-    var width=int(height*1/0.618)*2;
-
-    var aspect=width/height;
-    var pixelAspect=11.0/24.0;
-
-    var gradient=split(""," .:!/r(l1Z4H9W8$");
-    var gradientSize=size(gradient)-1;
-
-    var screen=[];
-    setsize(screen,width*height);
-
-    var light=vec3norm([-0.5,0.5,-1.0]);
-    var spherePos=[0,3,0];
-    var vec2_2_2=[2,2];
-    var vec2_1_1=[1,1];
-    var vec3_000=[0,0,0];
-    var vec3_00n1=[0,0,-1];
-    var vec3_111=[1,1,1];
-
-    print("\e[2J");
-    var stamp=maketimestamp();
-    for(var t=0;t<frame;t+=1) {
-        stamp.stamp();
-        for(var i=0;i<width;i+=1) {
-            for(var j=0;j<height;j+=1) {
-                var uv=vec2sub(vec2mul(vec2div([i,j],[width,height]),vec2_2_2),vec2_1_1);
-                uv[0]*=aspect*pixelAspect;
-                var ro=[-6,0,0];
-                var rd=vec3norm([2,uv[0],uv[1]]);
-                ro=rotateY(ro,0.25);
-                rd=rotateY(rd,0.25);
-                ro=rotateZ(ro,t*0.03);
-                rd=rotateZ(rd,t*0.03);
-                var diff=1;
-                for (var k=0;k<5;k+=1) {
-                    var minIt=99999;
-                    var intersection=sphere(vec3sub(ro,spherePos),rd,1);
-                    var n=vec3_000;
-                    var albedo=1;
-                    if (intersection[0]>0) {
-                        var itPoint=vec3add(vec3sub(ro,spherePos),vec3mul(rd,[intersection[0],intersection[0],intersection[0]]));
-                        minIt=intersection[0];
-                        n=vec3norm(itPoint);
-                    }
-                    var boxN=[0,0,0];
-                    intersection=box(ro,rd,vec3_111,boxN);
-                    if (intersection[0]>0 and intersection[0]<minIt) {
-                        minIt=intersection[0];
-                        n=boxN;
-                    }
-                    var tmp=plane(ro,rd,vec3_00n1,1);
-                    intersection=[tmp,tmp];
-                    if (intersection[0]>0 and intersection[0]<minIt) {
-                        minIt=intersection[0];
-                        n=vec3_00n1;
-                        albedo=0.5;
-                    }
-                    if (minIt<99999) {
-                        diff*=(vec3dot(n,light)*0.5+0.5)*albedo;
-                        ro=vec3add(ro,vec3mul(rd,[minIt-0.01,minIt-0.01,minIt-0.01]));
-                        rd=vec3reflect(rd,n);
-                    }
-                    else break;
-                }
-                var color=int(diff*20);
-                color=clamp(color,0,gradientSize);
-                screen[i+j*width]=gradient[color];
-            }
-        }
-        var s="";
-        forindex(var index;screen) {
-            s~=screen[index];
-            if (index+1-int((index+1)/width)*width==0)
-                s~="\n";
-        }
-        var elt=stamp.elapsedMSec()/1000;
-        print("\e[H",int(1/elt)," fps  \n",s);
-    }
-}
-
-var st=maketimestamp();
-var run=[0,0];
-var frame=1e3;
-if (size(runtime.argv())!=0) {
-    var n=num(runtime.argv()[0]);
-    if (!math.isnan(n)) {
-        frame=n;
-    }
-}
-st.stamp();
-main(frame);
-run[0]=st.elapsedMSec();
-use_raw();
-st.stamp();
-main(frame);
-run[1]=st.elapsedMSec();
-
-println("test 0: ",run[0]/1000,"s ",frame*1000/run[0]," fps");
+# ray tracing example
+# modified from Artem Yashin's project Console3D
+
+# MIT License
+# Copyright (c) 2021 Artem Yashin
+
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+use module.libmat;
+use std.runtime;
+use std.math;
+
+func() {
+    # allocate more spaces
+    runtime.gc.extend("str", 8);
+    runtime.gc.extend("vec", 8);
+}();
+
+var (max,min,sqrt,sin,cos,abs)=(
+    math.max,
+    math.min,
+    math.sqrt,
+    math.sin,
+    math.cos,
+    math.abs
+);
+
+var (vec2,vec3)=(
+    libmat.vec2.new,
+    libmat.vec3.new
+);
+
+var (vec2add,vec2sub,vec2mul,vec2div,vec2len)=(
+    libmat.vec2.add,
+    libmat.vec2.sub,
+    libmat.vec2.mul,
+    libmat.vec2.div,
+    libmat.vec2.len
+);
+
+var (vec3add,vec3sub,vec3mul,vec3div,vec3neg,vec3norm,vec3len,vec3dot)=(
+    libmat.vec3.add,
+    libmat.vec3.sub,
+    libmat.vec3.mul,
+    libmat.vec3.div,
+    libmat.vec3.neg,
+    libmat.vec3.norm,
+    libmat.vec3.len,
+    libmat.vec3.dot
+);
+
+var (rotateX,rotateY,rotateZ)=(
+    libmat.vec3.rx,
+    libmat.vec3.ry,
+    libmat.vec3.rz,
+);
+
+var use_raw = func() {
+    vec2 = func(x,y) {return [x,y];}
+    vec2add = func(v1,v2) {return [v1[0]+v2[0],v1[1]+v2[1]];}
+    vec2sub = func(v1,v2) {return [v1[0]-v2[0],v1[1]-v2[1]];}
+    vec2mul = func(v1,v2) {return [v1[0]*v2[0],v1[1]*v2[1]];}
+    vec2div = func(v1,v2) {return [v1[0]/v2[0],v1[1]/v2[1]];}
+    vec3 = func(x,y,z) {return [x,y,z];}
+    vec3add = func(v1,v2) {return [v1[0]+v2[0],v1[1]+v2[1],v1[2]+v2[2]];}
+    vec3sub = func(v1,v2) {return [v1[0]-v2[0],v1[1]-v2[1],v1[2]-v2[2]];}
+    vec3mul = func(v1,v2) {return [v1[0]*v2[0],v1[1]*v2[1],v1[2]*v2[2]];}
+    vec3div = func(v1,v2) {return [v1[0]/v2[0],v1[1]/v2[1],v1[2]/v2[2]];}
+    vec3neg = func(v) {return [-v[0],-v[1],-v[2]];}
+    vec2len = func(v) {var (x,y)=(v[0],v[1]); return sqrt(x*x+y*y);}
+    vec3len = func(v) {var (x,y,z)=(v[0],v[1],v[2]); return sqrt(x*x+y*y+z*z);}
+    vec3norm = func(v) {var t=vec3len(v); return vec3div(v,[t,t,t]);}
+    vec3dot = func(a,b) {return a[0]*b[0]+a[1]*b[1]+a[2]*b[2];}
+    rotateX = func(a,angle) {return [a[0],a[2]*sin(angle)+a[1]*cos(angle),a[2]*cos(angle)-a[1]*sin(angle)];}
+    rotateY = func(a,angle) {return [a[0]*cos(angle)-a[2]*sin(angle),a[1],a[0]*sin(angle)+a[2]*cos(angle)];}
+    rotateZ = func(a,angle) {return [a[0]*cos(angle)-a[1]*sin(angle),a[0]*sin(angle)+a[1]*cos(angle),a[2]];}
+}
+
+var clamp = func(value,_min,_max) {
+    return max(min(value,_max),_min);
+}
+var sign = func(a) {
+    return (0<a)-(a<0);
+}
+var step = func(edge,x) {
+    return x>edge;
+}
+
+var vec3abs = func(v) {
+    return [abs(v[0]),abs(v[1]),abs(v[2])];
+}
+var vec3sign = func(v) {
+    return [sign(v[0]),sign(v[1]),sign(v[2])];
+}
+var vec3step = func(edge,v) {
+    return [step(edge[0],v[0]),step(edge[1],v[1]),step(edge[2],v[2])];
+}
+var vec3reflect = func(rd,n) {
+    var d=vec3dot(n,rd);
+    return vec3sub(rd,vec3mul(n,vec3mul([2,2,2],[d,d,d])));
+}
+
+var sphere = func(ro,rd,r) {
+    var b=vec3dot(ro,rd);
+    var c=vec3dot(ro,ro)-r*r;
+    var h=b*b-c;
+    if (h<0.0) return [-1.0,-1.0];
+    h=sqrt(h);
+    return [-b-h,-b+h];
+}
+
+var box = func(ro,rd,boxSize,outNormal) {
+    var m=vec3div([1.0,1.0,1.0],rd);
+    var n=vec3mul(m,ro);
+    var k=vec3mul(vec3abs(m),boxSize);
+    var t1=vec3sub(vec3neg(n),k);
+    var t2=vec3add(vec3neg(n),k);
+    var tN=max(max(t1[0],t1[1]),t1[2]);
+    var tF=min(min(t2[0],t2[1]),t2[2]);
+    if (tN>tF or tF<0.0) return [-1.0,-1.0];
+    var yzx=[t1[1],t1[2],t1[0]];
+    var zxy=[t1[2],t1[0],t1[1]];
+    var tmp=vec3mul(vec3mul(vec3neg(vec3sign(rd)), vec3step(yzx,t1)),vec3step(zxy,t1));
+    outNormal[0]=tmp[0];
+    outNormal[1]=tmp[1];
+    outNormal[2]=tmp[2];
+    return [tN, tF];
+}
+
+var plane = func(ro,rd,p,w) {
+    return -(vec3dot(ro,p)+w)/vec3dot(rd,p);
+}
+
+var main = func(frame) {
+
+    var height=15*2;
+    var width=int(height*1/0.618)*2;
+
+    var aspect=width/height;
+    var pixelAspect=11.0/24.0;
+
+    var gradient=split(""," .:!/r(l1Z4H9W8$");
+    var gradientSize=size(gradient)-1;
+
+    var screen=[];
+    setsize(screen,width*height);
+
+    var light=vec3norm([-0.5,0.5,-1.0]);
+    var spherePos=[0,3,0];
+    var vec2_2_2=[2,2];
+    var vec2_1_1=[1,1];
+    var vec3_000=[0,0,0];
+    var vec3_00n1=[0,0,-1];
+    var vec3_111=[1,1,1];
+
+    print("\e[2J");
+    var stamp=maketimestamp();
+    for(var t=0;t<frame;t+=1) {
+        stamp.stamp();
+        for(var i=0;i<width;i+=1) {
+            for(var j=0;j<height;j+=1) {
+                var uv=vec2sub(vec2mul(vec2div([i,j],[width,height]),vec2_2_2),vec2_1_1);
+                uv[0]*=aspect*pixelAspect;
+                var ro=[-6,0,0];
+                var rd=vec3norm([2,uv[0],uv[1]]);
+                ro=rotateY(ro,0.25);
+                rd=rotateY(rd,0.25);
+                ro=rotateZ(ro,t*0.03);
+                rd=rotateZ(rd,t*0.03);
+                var diff=1;
+                for (var k=0;k<5;k+=1) {
+                    var minIt=99999;
+                    var intersection=sphere(vec3sub(ro,spherePos),rd,1);
+                    var n=vec3_000;
+                    var albedo=1;
+                    if (intersection[0]>0) {
+                        var itPoint=vec3add(vec3sub(ro,spherePos),vec3mul(rd,[intersection[0],intersection[0],intersection[0]]));
+                        minIt=intersection[0];
+                        n=vec3norm(itPoint);
+                    }
+                    var boxN=[0,0,0];
+                    intersection=box(ro,rd,vec3_111,boxN);
+                    if (intersection[0]>0 and intersection[0]<minIt) {
+                        minIt=intersection[0];
+                        n=boxN;
+                    }
+                    var tmp=plane(ro,rd,vec3_00n1,1);
+                    intersection=[tmp,tmp];
+                    if (intersection[0]>0 and intersection[0]<minIt) {
+                        minIt=intersection[0];
+                        n=vec3_00n1;
+                        albedo=0.5;
+                    }
+                    if (minIt<99999) {
+                        diff*=(vec3dot(n,light)*0.5+0.5)*albedo;
+                        ro=vec3add(ro,vec3mul(rd,[minIt-0.01,minIt-0.01,minIt-0.01]));
+                        rd=vec3reflect(rd,n);
+                    }
+                    else break;
+                }
+                var color=int(diff*20);
+                color=clamp(color,0,gradientSize);
+                screen[i+j*width]=gradient[color];
+            }
+        }
+        var s="";
+        forindex(var index;screen) {
+            s~=screen[index];
+            if (index+1-int((index+1)/width)*width==0)
+                s~="\n";
+        }
+        var elt=stamp.elapsedMSec()/1000;
+        print("\e[H",int(1/elt)," fps  \n",s);
+    }
+}
+
+var st=maketimestamp();
+var run=[0,0];
+var frame=1e3;
+if (size(runtime.argv())!=0) {
+    var n=num(runtime.argv()[0]);
+    if (!math.isnan(n)) {
+        frame=n;
+    }
+}
+st.stamp();
+main(frame);
+run[0]=st.elapsedMSec();
+use_raw();
+st.stamp();
+main(frame);
+run[1]=st.elapsedMSec();
+
+println("test 0: ",run[0]/1000,"s ",frame*1000/run[0]," fps");
 println("test 1: ",run[1]/1000,"s ",frame*1000/run[1]," fps");
\ No newline at end of file