1. A method of generating programming instructions for configuring an array of programmable logic cells which comprise logic elements and programmable switch assemblies, each of such switch assemblies including at least one signal input lead and at least one signal output lead; such method comprising, on a work station having a display screen, input means, and a programmed processor for generating on the display screen displays of symbols representing logic elements, switch assemblies and their connections and for processing input from the input means, the steps of: a. providing on the display screen a template representing an unprogrammed array of switches; and b. generating a programming instruction in response to signals from the input means, such signals representing (i) selection of an output lead of a switch and (ii) selection of a source from among (a) an input lead of the switch, (b) a logical one signal and (c) a logical zero signal; said generating step providing such programming instruction in a form usable by the array of cells to configure said switch assembly to connect the selected output lead to the selected source.