cos(x)*cos(y)
a Ghost

(1-cos(x))*(1-cos(y))
a Crypt

cos(x*y)
Waves around a Cross

1/sqr((x+1)²+y²)-1/sqr((x-1)²+y²)
Equipotential Surface

cos(x²+y²)/exp((x²+y²)/4)
the 'Blupp'

sin(1.25*s)+0.48*sin(3.75*s)
a Hat

cos(atn(x/y)*sgn(y)*8.0)/4*sin(sqr(x²+y²)*3)
a Red Rose

sqr(abs(1-abs(1-abs(1-abs(x*y+0.5)))))
'Carves'

(1-cos(x))*(1-cos(y))
two cosine hills

cos(sqr(x²+y²))
'Loop'

cos(log(sqr(x²+y²)/30+0.001))
'Peak'

abs(sin(4*x)+sin(4*y))/4*cos(sqr(x²+y²)*16)
'Ripples'

Holes and Hills

a Caramel Pudding