The Stomachion is a puzzle attributed to Archimedes and thus known as Archimedes’ Puzzle or the Loculus of Archimedes. The objective of the puzzle is to rearrange all of the the 14 pieces to make a specified shape.

Have a look at the following websites:-

https://illuminations.nctm.org/uploadedFiles/Content/Lessons/Resources/3-5/Stomachion-AS-ArchPuzzle.pdf

https://www.professorpuzzle.com/wp-content/uploads/2015/11/ArchimedesTangramPuzzleBook.jpg