Animated arctan(z) warping. Examples: https://dl.dropboxusercontent.com/u/15297093/cubes800_diag.gif and https://dl.dropboxusercontent.com/u/15297093/stripes800_diag.gif.

warping.py

import sys
import numpy as np
from scipy import ndimage
from scipy.misc import imread, imsave
 
def transform(X, Y, scale1, scale2):
    
    shape = np.float_(X.max()), np.float_(Y.max())
    
    X = X - shape[0]/2
    Y = Y - shape[1]/2
    
    points = np.arctan( (X + 1j*Y) / scale1)*scale2
    return np.real(points), np.imag(points)

def map_coordinates_color(img, coords, **kwargs):
    
    num_channels = img.shape[-1]
    shape = coords[0].shape
    
    res = np.zeros(shape+(num_channels,), img.dtype)
    for i in xrange(num_channels):
        res[...,i] = ndimage.map_coordinates(img[...,i], coords, **kwargs)
    
    return res

def animate(img, prefix="img_", num_frames=40, shape=(512,800), scale1=256, scale2=512, autofit=True):
    
    X, Y = np.mgrid[:shape[0], :shape[1]]
    X2, Y2 = transform(X, Y, scale1, scale2)
    
    if autofit:
        diff = X2.max() - X2.min()
        scale3 = np.round(diff/img.shape[0])*(img.shape[0]-1)/diff
        X2, Y2 = X2*scale3, Y2*scale3
    
    step = img.shape[0]/float(num_frames)
    ratio = img.shape[1]/float(img.shape[0])
    for i in xrange(num_frames):
        print >> sys.stderr, "Frame %d..."%i
        offset_x = i * step
        offset_y = offset_x*ratio
        aux = map_coordinates_color(img, [X2+offset_x,Y2-offset_y], mode='wrap')
        imsave("%s%03d.png"%(prefix, i), aux)

def main():
    filename = sys.argv[1]
    img = imread(filename)
    animate(img)

if __name__ == '__main__':
    main()