Designed by Tinkercad Modeling.
(Printed on a Monoprice Mini V1 3D printer, from Thingiverse thing 3610958, 2019,
PLA plastic, 2+3/8" high, 2+3/8" wide, 3/8" thick)

Three pieces assemble in a straightforward way to make a heart:



Further Reading
JigsSaw Heart Thingiverse Page,, from: https://www.thingiverse.com/thing:3610958