Straightforward
Place a letter in each empty circle, such that each of the given pieces can be found in the grid, without rotation or reflection. A question mark will denote a letter (i.e. a circle must be present) although it is up to you to work out which letter it represents. Multiple question marks on a single given piece may have different letters. For example, an "A??B" piece must appear in that orientation, and can be filled with "AAAB", "AABB", "ADEB" etc.
Example
For this example, we must place all four pieces into the given 3x3 grid. First consider the piece with 3 As. This piece can only go in one way, as rotations and reflections are not allowed. Then, place the piece with 3 Bs, as that piece can now only fit in one way. Proceed this way for the Cs and Ds. The puzzle is now solved.
Background
This puzzle type was invented by Johan de Ruiter.
Puzzles in this genre.
