#include <stdio.h>
typedef int xT;         /* x coordinate */
typedef int yT;         /* y coordinate */
typedef int coT;        /* rgb color value */

static void build(
    xT wd, 
    yT HG) 
{
    yT y;
    coT r;
    xT x;
    
    printf("P3\t%d %d\t255\n",wd*256,HG);
    for (y=0; y<HG; ++y) {
        for (r=0; r<256; ++r) {
            coT const g = 255 - r;
            coT const b = 0;
            for (x=0; x<wd; ++x) {
                printf("%03d %03d %03d ",r,g,b);
            }
            printf("\n");
        }
        printf("\n");
    }   
}

int main(
    int argc,
    const char * const argv[argc])
{
    build(32,1024);
    return 0;
}

// after compiling, run "a.out | pnmtopng >Color_gradient_illustrating_a_sorites_paradox.png" to obtain image