DFT 8x8 blocks (text based image) 

A video showing how adding together 64 different basis functions for each 8x8 block of an image with a different complex aplitiude can reconstruct the original image.
The amplitude of each basis function for each block is given by an 8x8 discrete fourier transform for that block.
For the background only 1 basis function is needed (with 0 amplitude) but for the text, local artifacts are present until almost all basis functions are used.
Pro Tip: Use the left right angled brackets (on the keyboard) to advance the image frame by frame
See: • Visualizing the discre... for a tutorial on how these animations were created!