Logic Masters Deutschland e.V.

Letter Series:
ABABA
ABBA
BBABB
AB Squared
Triangular Letters
Now I Know My ABCs

Rules:
Place 4 As, 3 Bs, and 2 Cs in every row, column, and 3x3 region.
Cages contain the exact same pattern of letters (without rotation or reflection). There may be other 2x2 areas in the grid with the same pattern.
Letters along thermometers are sorted in alphabetical order from the bulb end (as a slow thermometer sorts digits in increasing order).
Triangles: The sum of the squares of the number of As on one leg (vertical or horizontal segment) and the number of Bs on the other leg must be equal to the square of the number of Cs on the hypotenuse (diagonal segment). In other words, the triangle must satisfy this equation: (As on one leg)² + (Bs on other leg)² = (Cs on hypotenuse)². Each value in parentheses must be greater than 0.
For clarification, letters on vertices are part of both adjacent line segments.