Two colours

Using two colour paper, one black side and one white side, or as here on the figures one blue side and one red side.
From a square of two side paper, to get by folding, without any cut, a square with following aspect.
Of course with the smallest number of folds, and an area with one colour may be made of several parts.

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In 3D

We now want to wrap a cube (say 3cm side) with a two colour paper tape (one side black, one side white) so that the cube looks entirely black.
Smallest length of tape ?    Solution
Suplementary question : same question with a tetrahedron, an octahedron, a dodecahedron, an icosahedron
The case of tetrahedron is used in a current used object. which one ?    Solution

From a square of paper, still bicouloured, do a few cuts, but leaving the paper in one piece, then fold to get a cube with one colour (several solutions).
Here also ,we search for the most economical folding : shortest cut and largest cube.
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