#Sierpinski Pentagon

You may have seen the chaos game method of approximating Sierpinski's Triangle by plotting points half way to a randomly chosen vertex. Here I have taken the same approach using 5 vertices. The shortest code I could settle on included hard coding the 5 vertices, and there was no way I was going to fit it all into 140 characters. So I've delegated the red component to a simple backdrop, and used the spare space in the red function to define a macro to bring the other two functions under 140 too. So everything is valid at the cost of having no red component in the pentagon.

unsigned char RD(int i,int j){
#define A int x=0,y=0,p[10]={512,9,0,381,196,981,827,981,DM1,381}
auto s=99./(j+99);return GR(i,j)?0:abs(53-int((3e3-i)*s+j*s)%107);}

unsigned char GR(int i,int j){static int c[DIM][DIM];if(i+j<1){A;for(int n=0;n<2e7;n++){int v=(rand()%11+1)%5*2;x+=p[v];x/=2;y+=p[v+1];y/=2;c[x][y]++;}}return c[i][j];}

unsigned char BL(int i,int j){static int c[DIM][DIM];if(i+j<1){A;for(int n=0;n<3e7;n++){int v=(rand()%11+4)%5*2;x+=p[v];x/=2;y+=p[v+1];y/=2;c[x][y]++;}}return c[i][j];}

Thanks to Martin Büttner for the idea mentioned in the question's comments about defining a macro in one function to then use in another, and also for using memoisation to fill the pixels in an arbitrary order rather than being restricted to the raster order of the main function.

The image is over 500KB so it gets automatically converted to jpg by stack exchange. This blurs some of the finer detail, so I've also included just the top right quarter as a png to show the original look:

Sierpinski Pentagon

You may have seen the chaos game method of approximating Sierpinski's Triangle by plotting points half way to a randomly chosen vertex. Here I have taken the same approach using 5 vertices. The shortest code I could settle on included hard coding the 5 vertices, and there was no way I was going to fit it all into 140 characters. So I've delegated the red component to a simple backdrop, and used the spare space in the red function to define a macro to bring the other two functions under 140 too. So everything is valid at the cost of having no red component in the pentagon.

unsigned char RD(int i,int j){
#define A int x=0,y=0,p[10]={512,9,0,381,196,981,827,981,DM1,381}
auto s=99./(j+99);return GR(i,j)?0:abs(53-int((3e3-i)*s+j*s)%107);}

unsigned char GR(int i,int j){static int c[DIM][DIM];if(i+j<1){A;for(int n=0;n<2e7;n++){int v=(rand()%11+1)%5*2;x+=p[v];x/=2;y+=p[v+1];y/=2;c[x][y]++;}}return c[i][j];}

unsigned char BL(int i,int j){static int c[DIM][DIM];if(i+j<1){A;for(int n=0;n<3e7;n++){int v=(rand()%11+4)%5*2;x+=p[v];x/=2;y+=p[v+1];y/=2;c[x][y]++;}}return c[i][j];}

Thanks to Martin Büttner for the idea mentioned in the question's comments about defining a macro in one function to then use in another, and also for using memoisation to fill the pixels in an arbitrary order rather than being restricted to the raster order of the main function.

The image is over 500KB so it gets automatically converted to jpg by stack exchange. This blurs some of the finer detail, so I've also included just the top right quarter as a png to show the original look:

#Sierpinski Pentagon

You may have seen the chaos game method of approximating Sierpinski's Triangle by plotting points half way to a randomly chosen vertex. Here I have taken the same approach using 5 vertices. The shortest code I could settle on included hard coding the 5 vertices, and there was no way I was going to fit it all into 140 characters. So I've delegated the red component to a simple backdrop, and used the spare space in the red function to define a macro to bring the other two functions under 140 too. So everything is valid at the cost of having no red component in the pentagon.

unsigned char RD(int i,int j){
#define A int x=0,y=0,p[10]={512,9,0,381,196,981,827,981,DM1,381}
auto s=99./(j+99);return GR(i,j)?0:abs(53-int((3e3-i)*s+j*s)%107);}

unsigned char GR(int i,int j){static int c[DIM][DIM];if(i+j<1){A;for(int n=0;n<2e7;n++){int v=(rand()%11+1)%5*2;x+=p[v];x/=2;y+=p[v+1];y/=2;c[x][y]++;}}return c[i][j];}

unsigned char BL(int i,int j){static int c[DIM][DIM];if(i+j<1){A;for(int n=0;n<3e7;n++){int v=(rand()%11+4)%5*2;x+=p[v];x/=2;y+=p[v+1];y/=2;c[x][y]++;}}return c[i][j];}

Thanks to Martin Büttner for the idea mentioned in the question's comments about defining a macro in one function to then use in another, and also for using memoisation to fill the pixels in an arbitrary order rather than being restricted to the raster order of the main function.

The image is over 500KB so it gets automatically converted to jpg by stack exchange. This blurs some of the finer detail, so I've also included just the top right quarter as a png to show the original look:

#Sierpinski Pentagon

You may have seen the chaos game method of approximating Sierpinski's Triangle by plotting points half way to a randomly chosen vertex. Here I have taken the same approach using 5 vertices. The shortest code I could settle on included hard coding the 5 vertices, and there was no way I was going to fit it all into 140 characters. So I've delegated the red component to a simple backdrop, and used the spare space in the red function to define a macro to bring the other two functions under 140 too. So everything is valid at the cost of having no red component in the pentagon.

unsigned char RD(int i,int j){
#define A int x=0,y=0,p[10]={512,9,0,381,196,981,827,981,DM1,381}
auto s=99./(j+99);return GR(i,j)?0:abs(53-int((3e3-i)*s+j*s)%107);}

unsigned char GR(int i,int j){static int c[DIM][DIM];if(i+j<1){A;for(int n=0;n<2e7;n++){int v=(rand()%11+1)%5*2;x+=p[v];x/=2;y+=p[v+1];y/=2;c[x][y]++;}}return c[i][j];}

unsigned char BL(int i,int j){static int c[DIM][DIM];if(i+j<1){A;for(int n=0;n<3e7;n++){int v=(rand()%11+4)%5*2;x+=p[v];x/=2;y+=p[v+1];y/=2;c[x][y]++;}}return c[i][j];}

Thanks to Martin Büttner for the idea mentioned in the question's comments about defining a macro in one function to then use in another, and also for using memoisation to fill the pixels in an arbitrary order rather than being restricted to the raster order of the main function.

The image is over 500KB so it gets automatically converted to jpg by stack exchange. This blurs some of the finer detail, so I've also included just the top right quarter as a png to show the original look: