Battery Terminal Adapter from Lawn Style (flat) to Auto (round)?

[michaelm101]

I read in a post that many owners with multiple stored vehicles use a single, well-maintained lawn/tractor (300cca) battery to start their vehicles.

The terminals on the lawn batteries are flattish. Is there an adapter that can convert this flattish terminal to standard "round," or is this a DIY project?

Thanks in advance!