Most of us, when thinking about construction toys, we think of things like Lincoln Logs, Tinkertoys, Lego, and for the older kids, Erector sets. By far, the most popular building toy in history is Lego, still made today, and with almost countless variations and sizes and themes. There are even Lego amusement parks.
Lego's popularity really rose in the 1960s. I remember a neighbor having a set in 1967, and we played with his set for hours. I always liked my Tinkertoys set, but this was something altogether different.
In 1967, Mattel brought out "Tog'l". Tog'l was a construction set with colorful pieces--as Legos were--but there the similarities ended. Tog'l had several distinct advantages over Lego, but one major disadvantage that, in my mind, helped doom the product. (Never mind that Lego was entrenched and already had a huge following).
Tog'l were approximately 3/4" square blocks (and also a triangle) that had holes or pegs in each side. Some had one peg, some two. The pegs fit into other blocks' holes. In addition, each block had a door on a hinge that could swing open, allowing for all types of toy movement. Unlike Lego, and really it's chief advantage, is it was not limited to verticle stacking. You could connect blocks and snap them together on any side and in any configuration.
Joining the blocks were girders, hollow tubes, axles, wheels, panels and other interesting pieces. There were a number of sets, and a number of models could be made with each set.
After having played with Legos, I found Tog'l to be absolutely superior in every way. The sheer buidling flexibility you had was great.
However, as I mentioned, there was one big disadvantage to Tog'l. As with Lego, the piece were "friction fit" together, and snapped solidly. Lego's plastic was harder, but not brittle, it allowed you to push together pieces over and over, with little or no wear. In fact, I have never seen loose fitting Lego's. Tog'l softer plastic wore a little each time you pushed the pieces together. Eventually, the holes would wear to the point that they would be loose fitting. My first set, the Busy Builder set, I played with so much that almost all the pieces were ill-fitting. I would have to turn blocks around to find a hole that was not worn, or use the blue "pins", which had a tighter fit, for key connecting points. The longer you played with them, the worse it got. Lego pieces virtually never work out, Tog'l always did.
But that was really the only issue with these sets, as major as it is. One could buy more blocks and distribute the wear across more pieces, and perhaps that was not a bad idea.