- ➊ In the diagram N pills are hidden. A pill is a rectangle of size 3x1 or 1x3 cells.
- ➋ The value of a pill is the sum of the numbers in the three cells of the pill. There exists exactly one pill with every value from 1 to N.
- ➌ A number at the edge of the diagram indicates the sum of the values in the pill cells in the corresponding row resp. column.