Crystal Thumbnail of a Crystal puzzle.

Size:
7x7.
Elements:
C, R, Y, S, T, A, and L.
Groups: Twenty-one total.
The 7 rows.
The 7 columns.
The 7 septominos.
Instructions:
Precise details on group numbering.
Answer grids:

Puzzle Difficulty levels and Examples

Difficulty LevelLowHighExample
Easiest 2 2 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Easy 3 4 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Medium 5 8 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Difficult 9 12 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Challenging 13 14 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid