Increasing Distances

Rules

Fill in each circle with a number from 1 to X so that no number appears more than once and each circle has exactly one number. (X is the number of circles given.) Also, the (Euclidean) distance between the centers of the circles labeled 1 and 2 must be smaller than the distance between the centers of the circles labeled 2 and 3, which must be smaller than the distance between the centers of the circles labeled 3 and 4, and so on.

(Rules (modified) and example from PGP IB)

History of the puzzle

Invented by Erich Friedman (USA) in 2000. First appeared in WPC 2000/Part I. Actual puzzle used in competition can be seen in his website.

Appearances in the past WPCs

• WPC 2019/Round 9 by Ulrich Voigt
• WPC 2000/Part I by Erich Friedman