Dr. Halcyon Foster
@infinigon.bsky.social
I write math puzzles. I teach kids. I bake ridonkulous cookies.
I don’t have an opinion without knowing the dog, but I did adopt a puppy 3 weeks ago. This is Norman Goodboy.
November 17, 2025 at 10:27 PM
I don’t have an opinion without knowing the dog, but I did adopt a puppy 3 weeks ago. This is Norman Goodboy.
They have always hated the East Wing.
October 21, 2025 at 12:54 PM
They have always hated the East Wing.
Who wants to tell my daughter?
October 12, 2025 at 3:18 AM
Who wants to tell my daughter?
Hey look then! I made my first math art book!!
July 2, 2025 at 5:08 AM
Hey look then! I made my first math art book!!
I’d go old school. It’s an easy read packed with practical ideas.
May 5, 2025 at 5:20 PM
I’d go old school. It’s an easy read packed with practical ideas.
Over 2 million people on all 50 states and multiple countries protested the lawlessness of the trump administration and the nyt puts it below the fold without a headline and describes it as people protesting his “policies”. They are complicit in the destruction of democracy.
April 6, 2025 at 4:30 PM
Over 2 million people on all 50 states and multiple countries protested the lawlessness of the trump administration and the nyt puts it below the fold without a headline and describes it as people protesting his “policies”. They are complicit in the destruction of democracy.
Plural group names for dolls. But I like your implied grouping: “a chaos of dolls”
January 31, 2025 at 1:03 AM
Plural group names for dolls. But I like your implied grouping: “a chaos of dolls”
January 13, 2025 at 2:09 AM
One time, my kiddo asked me to cut his sandwich into fourths.
January 1, 2025 at 10:19 PM
One time, my kiddo asked me to cut his sandwich into fourths.
Happy Mathvent! Day 24!
December 24, 2024 at 3:39 PM
Happy Mathvent! Day 24!
Happy Mathvent! I forgot to post this 2 days ago. It’s probably my favorite problem I wrote this year.
December 24, 2024 at 3:23 PM
Happy Mathvent! I forgot to post this 2 days ago. It’s probably my favorite problem I wrote this year.
Happy Mathvent! Day 23. The penultimate puzzle.
December 23, 2024 at 11:40 PM
Happy Mathvent! Day 23. The penultimate puzzle.
Happy Mathvent! Day 21!
December 21, 2024 at 10:19 PM
Happy Mathvent! Day 21!
Happy Mathvent! Day 20! #iteachmath
Assume the squares are unique.
Assume the squares are unique.
December 20, 2024 at 2:59 PM
Happy Mathvent! Day 20! #iteachmath
Assume the squares are unique.
Assume the squares are unique.
Happy Mathvent! Day 19!
December 19, 2024 at 2:46 PM
Happy Mathvent! Day 19!
Happy Mathvent! Day 18! By unique in this problem, I mean non-congruent.
December 19, 2024 at 6:14 AM
Happy Mathvent! Day 18! By unique in this problem, I mean non-congruent.
Happy Mathvent! Day 17!
December 17, 2024 at 5:03 PM
Happy Mathvent! Day 17!
Happy Mathvent! Day 16! #iteachmath
December 16, 2024 at 2:29 PM
Happy Mathvent! Day 16! #iteachmath
Happy Mathvent! Day 14!
December 14, 2024 at 5:14 PM
Happy Mathvent! Day 14!