Scratch Project having fun with unit conversions

Given a list of facts such as;

- ("hr", "min", 60)
- ("min", "second", 60)
- ("second", "ms", 1000)

and a query such as ("hr", "ms", 5) we can convert between units.

Examples

query ("hr", "ms", 5) -> 3.6e+6 (approximately)

Note there's no need to repeat a fact, we should be able to convert backwards

Given facts:

- ("hr", "min", 60)
- ("min", "second", 60)
- ("second", "ms", 1000)

we can convert ms to hr