I had a toy as a kid that was somewhere between this Lectron system and the 75 in 1 Electronics kits that Radio Shack sold. Components were on square blocks ea

I had a toy as a kid that was somewhere between this Lectron system and the 75 in 1 Electronics kits that Radio Shack sold. Components were on square blocks each (red plastic). Small clips would hold blocks edge to edge. Wiring was by means of, like the "75 in 1", spring terminals in the corners of the blocks — a small steel clip was inserted into the spring terminal — just the right length to bridge the gap between adjacent blocks. Simple stuff as I recall: battery, light bulb, switch. If there was a transistor or two it went over my head at so young an age. I was at the "hook up battery to a bulb" stage of electronics learning.