Education-HyperXtreme 
Size:
21x21.
Elements:
E, D, U, C, A, T, I, O, and N.
Groups: One hundred forty-seven total.
The 36 rows in the upper left, upper right, lower left, and lower right puzzles.
The 36 columns in the upper left, upper right, lower left, and lower right puzzles.
The 36 3x3 squares in the upper left, upper right, lower left, and lower right puzzles.
The 8 diagonals in the upper left, upper right, lower left, and lower right puzzles.
The 9 rows in the center puzzle.
The 9 columns in the center puzzle.
The 9 3x3 squares in the center puzzle.
The 4 3x3 inner squares in the center puzzle.
Instructions:
Precise details on group numbering.
Answer grids:
Puzzle Difficulty levels and Examples
| Difficulty Level | Low | High | Example |
| Easiest | 2 | 2 | |
| Easy | 3 | 4 | |
| Medium | 5 | 8 | |
| Difficult | 9 | 14 | |
| Challenging | 15 | 20 | |
| Tournament | 21 | 29 | |
| TournamentPlus | 30 | 45 | |
| Perplexing | 46 | 60 | |