Probably the most insane piece of code written ever...

Here is the code which uses trigonometry for 3D rotation, z-buffer depth calculations, and luminance shading. Boundary checks guarantee valid coordinates, while time delays control animation speed:

         k;double sin()
     ,cos();main(){float A=
   0,B=0,i,j,z[1760];char b[
 1760];printf("\x1b[2J");for(;;

){memset(b,32,1760);memset(z,0,7040) ;for(j=0;6.28>j;j+=0.07)for(i=0;6.28

i;i+=0.02){float c=sin(i),d=cos(j),e= sin(A),f=sin(j),g=cos(A),h=d+2,D=1/(c* he+fg+5),l=cos (i),m=cos(B),n=s
in(B),t=chg-f* e;int x=40+30D (lhm-tn),y= 12+15D*(lhn +tm),o=x+80y, N=8*((fe-cdg )m-cde-fg-l dn);if(22>y&& y>0&&x>0&&80>x&&D>z[o]){z[o]=D;;;b[o]= ".,-~:;=!#$@"[N>0?N:0];}}/#!!-/ printf("\x1b[H");for(k=0;1761>k;k++) putchar(k%80?b[k]:10);A+=0.04;B+= 0.02;}}/####*****!!=;:~ ~::==!!!********!!!==::- .,~~;;;========;;;:~-. ..,--------,/

source: https://www.a1k0n.net/2011/07/20/donut-math.html