On https://puzzle.telegnom.org/ generate a puzzle shape as on image for our pendant and Download SVG

Jitter: 0%, Tiles: 2x1, Size: Doesn't matter

Insert Shape - Heart to XCS and Export as SVG

You can use your own heart shape if you want

You need to remove outer lines from puzzle shape and keep only puzzle shape. You can do it easy with Node tool select nodes (with SHIFT key) of puzzle shape and Copy → Paste

Join heart shape and puzzle shape together like on image and be careful to join it well otherwise your laser will not cut right

Save as SVG and import it to XCS

Insert Text for Name and Birthdate, Insert Shape (optional), Insert Circles for hooks

Your heart pendant is done :-)

I used 100%power|4mm/s speed and 1 pass for cutting and 78%power|130mm/s speed for engraving for 4mm poplar plywood Air Assist ON (don't forget to turn on - I forgot :-))