Tesseract

Sit start down low around the corner to the right from Hexahedron on a good edge. Move up into an undercling directly above the edge and bring your left hand up to a sloping hold higher up. Get your feet onto the start edge and use small crimps to reach the top.

Around the corner and to the right of Hexahedron. If at the Diamond boulder, walk straight uphill and to the left of the boulder and you will be staring at it.