Oortmas presents and twinkles alterations

I noticed that some folks have different sizes of their wrapped gift boxes. How do I change the size of them? Also, does anyone know how to change the direction of the Twinkles? I only seem to get it to lay horizontally.

I believe it is based on the block its placed like Vex mentioned about the plants.

Changing Size of presents changes automatically once placed next to other presents, given you can chisel it to change size but after 4-5 min it revert back to the size it was at originally