The Sphere function has d local minima except for the global one. It is continuous, convex and unimodal. The plot shows its two-dimensional form. The function is usually evaluated on the hypercube x i ...

[DaveMakesStuff] demonstrates a great technique for 3D printing a sphere; a troublesome shape for filament-based printers to handle. As a bonus, it uses a minimum of filament. His ideas can be ...