These next set of pictures show the new single-coil relays which were also used in the batch of 6 for the Festival of Britain in 1951. You will also notice the oil-filled capacitor has gone, and in one picture another capacitor is in place. This is most likely the capacitor used to give M. speculatrix its 'memory' when bumping and avoiding obstacles to ensure another cycle of avoidance strategy when the contact with the obstacle has stopped.
![ELSIE - improved version [note new relay and capacitor]](http://cyberneticzoo.com/wp-content/uploads/2009/09/Ivall_Malone_Tortoise-1024x841.jpg "Ivall_Malone_Tortoise")
Another subtle change is the end mounting point on the drive motor. Previously this was held by a bush in the side front wheel fork, whereas now it is a bored out hole. Here is a still from a film clip showing this aspect.
