Programmable Materials A Substrate, whose shape can be programmed –engineer global shape –dynamic shape change Structure composed of mechanical cells –coordinate local shape changes to achieve global shape A Mechanical Cell Springs can actively change their length and modify cell shape (adapted from model by Odell, et al)

2D Structure: Ring composed of Mechanical Cells cleave fingers eye folds bulb neurulation gastrulation ring of active cells

Engineering Global Shape from local shape changes Cleave Fingers red cells are actively changing their shape

Programming a Cell’s local interactions Eyefolds

3D Structure: Sheet composed of Mechanical Cells

Simple Folds on a Cellsheet Folds can be characterized by angle curvature apical or basal Folds can be composed to create more complex structures large angle, small curvature small angle, more curvature 90 degree folds with different curvatures

Shapes formed by a Composition of Folds