Knife Holders

On 2021-08-18, New Zealand re-entered COVID-19 Alert Level 4, aka lockdown. One upside of lockdown is more time for arts and crafts.

Challenge 1: Construct with (pencil and) straightedge and compass only a regular pentagon. Solution here.

Challenge 2: Construct with compass only (the vertices of) a regular pentagon. Solution here.

Challenge 3: Construct with compass and straightedge only a regular heptagon (7 sides). 🥺 Anti-solution 3 here.

Trivia: Neodymium magnets were invented in what decade of the 20th century? Answer here.