Finally, a Si triangular pyramidal needle was fabricated by photolithography and anisotropic TMAH (25.0 wt.%, 70°C) wet etching. The height of the needle was 0.1 mm. It is clear that the vertex of the ...

“Bille” is the first-ever monostable tetrahedron, or a pyramid-like shape with four triangular faces that has one stable ...