Ключевые слова: abstract, art, backgrounds, black, computer, cube, cubicle, decoration, design, dirty, endless, escher, experiment, eyesight, frame, geometric, graphic, gray, illusion, illustration, imagine, impossible, instrument, item, join, loop, magic, mobius, novelty, optical, originally, paper, pattern, psychiatrist, shape, square, strip, symbol, technical, test, think, three dimensional, triangle, trickery, tunnel, vasarely, wall, wallpaper, white,