This program illustrates how a regular heptagon can be dissected into eight pieces, which can then be re-arranged into a larger heptagon - but with a heptagonal hole in the middle! It requires 'BBC BASIC for Windows' or 'BBC BASIC for SDL 2.0', alternatively you can run it in your browser here (in Facebook's mobile app use 'Open in external browser'): https://wasm.bbcbasic.net/bbcsdl.html?app=bbcbasic.co.uk/webapps/dissection 10 REM Dissection of a regular heptagon into two heptagons 20 REM by R