The company
Green Lizard Technologies Limited is a small company registered in England and run from The Cube, Arngrove Court, on Barrack Road.
A web page is only useful to a stranger for four things: the registered name, the place, a way to reach somebody, and whatever the company has put its name to. Those are set out below. The rest of it is the sort of thing that gets decided in a conversation, and the address at the end of this page reaches a person, not a ticket queue.
One small count
Shunting with a single siding is the oldest sorting machine there is: wagons arrive in order, each one is either pushed into the siding or sent straight out, and anything in the siding can only leave from the end it went in. That one restriction is enough to rule out most orders. The count of the ones that survive is the Catalan numbers, and against the factorial they fade away fast.
| Wagons | Orders in principle | Reachable by one siding | Share |
|---|
Pick a row to read it out.
Wagons 1 to 4 arrive in order. Push one into the siding, or pull the last one out of it; wagons also leave straight from the arrival road.
Fourteen of the twenty-four possible orders can be produced this way. The other ten cannot, whatever you do.
The smallest order no siding can produce is 3, 1, 2: to get the third wagon out first, the first two must be in the siding — and then they can only come out in the reverse of the order they went in. Every count on this page was checked by generating every reachable order for up to nine wagons and comparing it with the formula.
On Google Play
It has nothing to do with the rest of the business — one listing, made for its own sake. Switchyard is a routing puzzle: trains leave their sidings on a timer, and you throw the points so each reaches the depot matching its colour without two of them ever sharing a length of rail. It runs with no connection, no account and nothing sold inside it.
Switchyard com.railyard.switchyard Privacy policy →
Contact
Green Lizard Technologies Limited
Newcastle upon Tyne, United Kingdom · office@greenlizardtechnologies.best
Android and Google Play are Google LLC's marks. Nothing on this site is made with Google or endorsed by them; the company simply has one listing on their store.