PIGTIKAL (puzzles in geometry that I know and love)
Anton Petrunin
HN submission. Found in a submission link or body. Submitters do not count as commenters in the main ranking; a submission is not an endorsement.
Abstract
Problems for the graduate students who want to improve problem-solving skills in geometry. Every problem has a short elegant solution -- this gives a hint which was not available when the problem was discovered.
arXiv comments
Second printing, 195 problems, 156 pages, 66 figures