Ink and pencil
Jimmi Whitcher (Jimmi-The-Sadist)
Here, we see impossible triangle and endless staircase in cubist style.
Artist's deviantART profile http://jimmi-the-sadist.deviantart.com
Cubist Escher
The image was found at http://jimmi-the-sadist.deviantart.com/art/Cubist-Escher-81869512