The gray generator can be used to generate gray shapes.
http://254shadesofgrey.com/elp/120?w=200&h=100
http://254shadesofgrey.com/rect/120?w=200&r=100
Want gradients? We can do those too!
Url Format: http://254shadesofgrey.com/gray/Graydient?b=[Starting Shade]&e=[Ending Shade]&w=[Width]&h=[Height]&s=[shape ("c" for ellipse, "r" for rectangle)]&a=[Angle to rotate the gradient]
http://254shadesofgrey.com/gray/Graydient
http://254shadesofgrey.com/gray/Graydient?b=50&e=120&a=45&s=c