Spinning Donuts

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <io.h>	// Visual Studio
//#include <unistd.h>	// Linux

int main() {
    int k;
    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 sini = sin(i),
                    cosj = cos(j),
                    sinA = sin(A),
                    sinj = sin(j),
                    cosA = cos(A),
                    cosj2 = cosj + 2,
                    mess = 1 / (sini * cosj2 * sinA + sinj * cosA + 5),
                    cosi = cos(i),
                    cosB = cos(B),
                    sinB = sin(B),
                    t = sini * cosj2 * cosA - sinj * sinA;
                int x = 40 + 30 * mess * (cosi * cosj2 * cosB - t * sinB),
                    y = 12 + 15 * mess * (cosi * cosj2 * sinB + t * cosB),
                    o = x + 80 * y,
                    N = 8 * ((sinj * sinA - sini * cosj * cosA) * cosB - sini * cosj * sinA - sinj * cosA - cosi * cosj * sinB);
                if (22 > y && y > 0 && x > 0 && 80 > x && mess > z[o]) {
                    z[o] = mess;
                    b[o] = ".,-~:;=!*#$@"[N > 0 ? N : 0];
                }
            }
        }
        system("cls");
        for (k = 0; 1761 > k; k++)
            putchar(k % 80 ? b[k] : 10);
        A += 0.08;
        B += 0.02;
    }

    return 0;
}

 

Donut math: how donut.c works