Trying to create a true smooth-sided pyramid, Sneferu’s architects began with the same steep angle and inward-leaning courses of stone they used to create step pyramids. When this began to show signs of stress and instability around halfway up its eventual 105m height, they had to reduce the angle from 54 degrees to 43 degrees and begin to lay the stones in horizontal layers. This explains why the structure has the unusual shape that gives it its name.
Most of its outer casing is still intact, and inside (closed to visitors) are two burial chambers, the highest of which retains its original ancient scaffolding of great cedar beams to counteract internal instability. There is also a small subsidiary pyramid to the south as well as the remains of a small funerary temple to the east. About halfway towards the cultivated area to the east are the ruins of Sneferu’s valley temple, which yielded some interesting reliefs.