For anyone having trouble please read – Osmo Tangram Classic Review

If you are having trouble getting the tablet to recognize the pieces make sure that the tablet asked you for permission to use the camera. When I first installed it never asked me for permission so the camera wasn’t even working. I deleted app then reinstalled, this time when first staring up app asked for permission to use camera and now app works just fine.
Review by jo.av on Osmo Tangram Classic.