Prototype wings were made from pipe cleaners sandwiched between two layers of material coated in PVA glue. Pipe cleaner wire proved too thin to hold its position against the resistance of the wings. Florist wire for the wing armature gives greater control during folding and unfolding.

Sleeping imps usually hang upside down like bats.

Simple versions of these sleeping imps will be used for a few scenes, their wings folded around them covering their bodies.

A square box section in the neck makes it easier changing heads from sleeping to awake. Early imps were made from plasticene but these are being replaced with better models made from from sculpey.com as this is much more hard wearing.