Pd has object, message, and number boxes, with inlets always on top and outlets on bottom

A Pd patch is built from three visible box types, distinguished by shape: object boxes (rectangular) run a named function; message boxes (right-side indentation) hold a fixed value/message sent when clicked; number boxes (flat upper-right corner) show and let you drag a live value. Every box has inlets along its top edge and outlets along its bottom edge, and you connect an outlet to an inlet - always in that direction, top-to-bottom. This spatial convention makes signal flow readable at a glance. Pd also has two modes: edit mode (for wiring/programming) and execute mode (for running and dragging values), toggled with Ctrl-E.

Examples

osc~ 440 (object box) fed by a dragged number box on its left inlet; a message box ‘0’/‘1’ clicked to toggle sound. Inlets top, outlets bottom on all three.

Assessment

Name the three box types and the visual cue that distinguishes each; state which edge holds inlets and which holds outlets, and the legal direction of a connection.