There are more than one subjects in the Growtopia Wiki using this name.
The Tangram Blocks are blocks which appear in tangram black and white designs of different varieties, labelled from A to L.
One tree can drop any types of Tangram Blocks, but the types it will yield are unknown until it is harvested. The tree displays question marks in the place of items when ready to harvest.
Glitched Tangram Seeds
See main article: Glitch Seeds