As easy as ABC/en

Instructions

   

Enter the letters from 'A' to 'C' into the diagram, so that in every row and every column every letter occurs exactly once; in every row and every column one field remains empty. The letters at the borders indicate the letter that comes first in the corresponding row or column.

 

Variants

• Depending on the size of the puzzle the letters from 'A' to 'D' or from 'A' to 'E' and so on, can be used. Usually one or two fields per line remain empty.
• The letters at the borders don't give the first, but the second letter in the corresponding row or column.
• Skyscrapers: Additionally in every field with a letter a digit is placed to form all given combinations of letters and digits.