Below is a mechanism I believe may be a possible interpretation of the toys page. I have made this little simple device and will explain it. I however have not attached it to a wheel as the device I have made is to flimsy, it was just for testing the principle which has good results. If two of these devices or maybe even just the one were put into a wheel, it might perpetuate. I really encourage people to please take a good look at this and build it for themselves.
The diagram is not drawn with 100% accuracy, but its close.
At the top, weight "A" falls out and up while weight "B" falls in and up. At the bottom, the device does the reverse.
At the end of the weighted right-angled levers are where the weights are pivoted on the wheel. The cross bar (that connects the two weighted levers together) acts as a push rod to lift the weights because the weights lean on that push rod causing a sideways movement (Like that on the toys page) and the weights lift up. At the top of the wheel, weight "A" is out by the rim, the second weight "B" is closer to the axle, when they get to the bottom of the wheel, they swap places as you can see in the drawing. The top two weights can over balance the bottom two weights a full half turn and over through the momentum as I have tested this by attaching 4 weights on a wheel in the current drawn position but is that enough so that they swap, if so, then it will perpetuate. (Notice the pentagram shape within the mechanism)
They do indeed swap at roughly those positions drawn, its just a matter of is the overbalance great enough? I'm sure this could be worked on, I have only just discovered this and not tested it in a wheel. But Please feel free to build it and even improve on it, im sure this has a good chance.
Edit: The two mechanism may even be connected to improve the lifting of the weights.
Alex