- on Miscellaneous Electronics
- Published in issue 7/2010 on page 60
(Summer Circuits 2010 article)
Each grid uses figures from the hexadecimal system, i.e. from 0 to F. Fill in each grid in such a way that all the hexadecimal figures from 0 to F (0 to 9 plus A to F) are used once and once only in each row, column, and square of four boxes (marked by a bolder outline). Certain figures have already been entered in the grid to define its starting situation. Free download!