Some iPhone and iPad users may occasionally notice that their iPhone app icons show up as blank white or grey icons with a grid like appearance on them of a cross and circles. If you’ve never seen ...

Have you ever seen a proper Venn diagram with four overlapping circles? No, because it’s impossible. Venn himself discovered this and came up with a clever fix, but this only begot deeper ...

The Geometry of Compasses; or, Problems Resolved by the mere Description of Circles, and "the Use of Coloured Diagrams and Symbols". By Oliver Byrne. (London: Crosby Lockwood and Co., 1877.) ...