Map folding ($2 \times 2)$
Robert Dickau, via Wikimedia Commons. CC BY-SA 3.0.
The number of distinct ways to fold a $2 \times 2$ rectangle into a unit square.
Value: $8$
Updates
-
Lower bound: $8$
Reference unknown
[via Number of ways of folding an n X n sheet of stamps. - OEIS] -
Upper bound: $8$
Reference unknown
[via Number of ways of folding an n X n sheet of stamps. - OEIS]