The flour tower, cut from card

SCION 02, after Lotte Reiniger's silhouette theatre

A sack with no face must decide in silhouette alone.

Made of

Black card on a lamp-lit screen of layered tissue. The sack is five cut pieces on four pins: a pooled bottom lobe, an upper lobe, a tied neck and two corner ears. Each lobe is taken from a cut library of 343 pieces (49 fullnesses by 7 squashes), each set trimmed so the body keeps the same area at its fullness. The tower, plate, knife, penny and table are cut card with punched holes the lamp shows through; spilled flour is cut heaps and cut flecks, the landing dust is tissue.

Moved by

Hand-set key poses, laid under the camera every second frame (12 exposures a second). Between keys the rigid pieces turn about their pins by eased steps; flinch, notice, prop, brace, leap and landing are held substitutions of new pieces on the hit frame. The ears hang on a damped spring that lags the neck. From 14.5 s the sack's base pin is solved: the whole sack tips on its tower-side corner until its upper lobe rests on the tower's cut face with a hairline of light between, and the tower's lean drops back 0.8 degrees under it. The fourth cut's blade tip strikes the penny's rim and flicks it up; it falls under constant gravity onto the neck. In the gather, flecks carry fixed shares of the heaps to the neck in eight batches of twelve, and when a batch has landed the cutter lays in the next fuller pieces from the library.

Measured from the render

Score	Choice	Measured

Every number comes from the drawn pieces: the sack's area is a pixel count of its body pieces in an offscreen mask, the gap is the distance between the sack's and the tower's card outlines, and the onsets are the first frames where those measures change. The full trace is in window.PAE_TRACE.