Based on The square and the compass
This is a new kind of challenge proposed on Meta Puzzling SE. Any discussion about the general type of puzzle (rather than this particular one) can be done there.
The robbers' post is given here.
You have a compass and a pencil but no scale/straightedge. You need to decide upon a construction task that can be achieved accurately in a finite number of moves. The following moves are valid.
- Make the compass radius equal to the distance between two already marked points.
- Draw a circle with any marked point as centre.
- Use any intersection of arcs/circles as a marked point.
- Select a continuous region (either an arc or a 2D region) and mark an approximate point. For example, I could draw an arc and then mark a point that is approximately (but not exactly) at the centre.
For example, a task could be "find the midpoint of a line segment" or "mark 5 points that form a regular pentagon"
Your challenge will be scored by the amount of time it remains unsolved. At the end of this month (31 Jan), you must post the solution(s) to any unsolved challenges. You can make up to 3 posts, and your total score will be the sum of the individual scores.