Equation:
z =
Enter any function on x and y constructed with operators:
+, -, * and /
and using functions:
abs, acos, asin, atan, atan2, ceil, cos, exp, floor, log, max, min, pow, pulse, random, round, sgn, sin, sqrt, and tan

Samples:
z = sin(y)
z = sin(x)
z = pulse(x)
z = sgn(x)
z = (x*x)/10
z = (y*y)/10
z = sin(sqrt(x*x + y*y))
z = cos(sqrt(x*x + y*y))
z = sqrt(25 - (x*x + y*y))
z = 2/sqrt(x*x + y*y)