A specially designed mask controls the arrangement of conductive materials that form a source and drain of a transistor. Designing the mask can be costly and time-consuming, which means that the testing of a circuit involving a transistor can also be costly, time consuming and a barrier towards efficient circuit development and testing. Accordingly, the present invention provides a pre-fabricated, general-purpose pattern comprising an array of conductive islands. The pattern is used as a source and a drain terminal for the formation of a thin-film transistor and as a conductive source for the formation of other electrical components upon the array.