Illuminated house number

An interlocking display panel assembly comprises a pair of end elements for attachment to a supporting surface, at least one intermediate element having an indicia displaying surface locatable in an interlocking relationship between said end elements to form an integral planar assembly, illumination means in said at least one intermediate element for illuminating said indicia displaying surface, each said element slidably engaging an adjacent said element by means of a tongue-and-groove arrangement having a dovetail tongue interlocking with a complementary groove to lock adjacent said elements against relative lateral displacement, male and female portions of said tongue-and-groove arrangements on opposite sides of said intermediate element being arranged in a complementary manner so that as many intermediate elements can be fitted together in a row as desired, respective contact means provided on opposing surfaces of adjacent interlocking elements so as to come into abutting contact when said male and female portions are fitted together and thereby transfer electrical power between adjacent elements, and one of said end elements including means for providing power to the assembly, and wherein said tongue-and-groove arrangements are tapered along an axis along which they are slid together to permit insertion from only one direction and to inhibit further insertion when all the elements are properly aligned.