Mathematicians are a Hungry Bunch

After yesterday's donut, today it's the Ding Dong Surface. Thanks to Alex who originally pointed me to the Kiss Surface (also named after junk food).

>>> p = Plot()
>>> p[1] = sqrt(1-y)*y, [x,0,2*pi,60], [y,-1,4,100], 'mode=cylindrical'



By the way, the torus shown yesterday can be plotted with:

>>> a,b = 1, 0.5
>>> p[2] = (a+b*cos(x))*cos(y), (a+b*cos(x))*sin(y), b*sin(x), [x,0,2*pi,20], [y,0,2*pi,20]

However, at writing there is a hang bug with trig functions in the new SymPy core, so this may or may not work when you try it.