Pyxplot 
Examples  Chequer board 
Using the colormap plot style with the fft command to draw a diffraction pattern (III) The Fourier transform of a circular chequerboard pattern, plotted using the colormap plot style. Script# Definition of function representing a chequer board pattern chequer(x,y) = (floor(x)+floor(y))%2 * tophat(hypot(x,y),3) # Take FFT of disk fft [40:40:0.1][40:40:0.1] fft() of chequer() w = unit(5*cm) set numerics complex set nogrid set key below set nocolorkey set sample grid 300x300 set size w square set multiplot set nodisplay # Plot realspace image plot [4:4][4:4] chequer(x,y) with colormap # Plot Fourierdomain image set origin w+unit(5*mm),0 set axis y right plot [2.5:2.5][2.5:2.5] abs(fft(x,y)) with colormap set display refresh
