This puzzle appears in "Challenge Your Brain Math & Logic Puzzles" (Dave Tuller & Michael Rios, Puzzle Wright Press).
Puzzle and Goal
An unsolved puzzle consists of a rectangular grid with letters in some of the cells.
The goal is to divide the grid into regions that satisfy the clues.
The solved grid must satisfy the following conditions:
Each region contains exactly one letter, which indicates the number of cells in that region (A=1, B=2, etc.).
If two regions have the same letter, they're shaped and oriented the same way.