While it might look like a brain-bending puzzle, Mia Schmallenbach’s Meeting Knives Set actually features a brilliant design allowing four different kitchen knives: a paring knife, a carving knife, a chef’s knife and a filleting knife to all stack inside each other on a single block of steel. All of these knives nest together like Russian-dolls and fit perfectly inside a big stainless-steel, or wooden block.
The full-metal set, made by French cutlery manufacturer Deglon, will cost you about $920 (if you can find it in the US). The wood-encased set is a more reasonable $490.
The proportions of each knife were apparently determined by the Fibonacci sequence.
The Fibonacci sequence starts with 0, 1 and continues by adding the previous two numbers together: 0, 1, 1, 2, 3, 5, 8 and so on. It can then be used to make shapes. Plotting squares whose sides are the length of successive Fibonacci numbers and then drawing an arc through their opposite corners will give the Golden Spiral, a shaped found in nature: the nautilus shell, for example. By making this shape, along with others suggested by the sequence, Schmallenbach came up with the design