Torus (0.4^2-(0.6-(x^2+y^2)^0.5)^2)^0.5 Ripple sin(10(x^2+y^2))/10 Tube 1/(15(x^2+y^2)) Bumps sin(5x)*cos(5y)/5 Cone (x^2+y^2)^0.5 Functions by Corrado, friend of Gianni Stairs (sign(-.65-x)+sign(-.35-x)+sign(-.05-x)+sign(.25-x)+sign(.55-x))/7 Pyramid 1-abs(x+y)-abs(y-x) Paper Plane sign(x) * atan(x*80)/6 * sign(-y-x+1) * sign(-y+x+1)*5 - 1.01 Green Cross .1 - sign(sign((x*12)^2-9)-1 + sign((y*12)^2-9)-1)/2 Mosque Dome .7/log(x^2+y^2)+.6 Roof 1-abs(y) Windmill sign(x*y) * sign(1-(x*9)^2+(y*9)^2)/9 Floppy Disc (1-acsc((x*4)^2+(y*4)^2))/1000 Triangle (1-sign(-x-.51+abs(y*2)))/3 * (sign(.5-x)+1)/3 Top Hat (sign(0.2-(x^2+y^2)) + sign(0.2-(x^2/3+y^2/3)))/3-1 Letter A ((1-sign(-x-.9+abs(y*2)))/3*(sign(.9-x)+1)/3)*(sign(x+.65)+1)/2 - ((1-sign(-x-.39+abs(y*2)))/3*(sign(.9-x)+1)/3) + ((1-sign(-x-.39+abs(y*2)))/3*(sign(.6-x)+1)/3)*(sign(x-.35)+1)/2 Letter O (-sign(0.2-(x^2+y^2)) + sign(0.2-(x^2/3+y^2/3)))/9 Letter V sign(x-1+abs(y*2))/3 + sign(x-.5+abs(y*2))/3 Intersecting Fences .75/exp((x*5)^2*(y*5)^2)