Tessellations is an iPhone app developed by David Rasch that offers a unique and creative way to create tessellation shapes. With a variety of shapes like triangles and squares to choose from, users can manipulate and modify these basic shapes by "drawing" with their fingers. Unlike traditional painting apps, this app feels more like precision drawing with a ruler, akin to vector drawing. The app ensures that the shapes tessellate seamlessly as users draw, maintaining geometric precision. Additionally, users have the freedom to experiment with different colors, adding an extra layer of creativity to the process. Tessellations provides an engaging and entertaining experience for users looking to explore geometric artistry.