QuickBitMap(z, anObject) displays a raster image of z.

z had to be a matrix. In a raster image, the x and the y coordinates are simply the column and row indexes: you cannot change them.

set {x, y, z} to QuickFormulaMatrix({-1, 1}, {-1, 1}, "tan( pi/4*x*y)")
QuickBitMap(z, "tan(pi/4.x.y)")

Import script