Cheapest way to have a 'track' on the garden for kids?

[Anonymouse2019]

We've got quite a big garden and 2 young children. They love playing on little trikes and Cosy Coupé but the lawn is quite uneven so they get stuck.

We're looking for a reasonably low-cost solution (flattened cardboard boxes don't work) to lay a MOVABLE track in the garden for them to ride on.

We've looked at lots of options but to create a biggish track wide enough for the toddler car, it'll be mega bucks. The plastic grid-like structures might work best but again, lots of plastic, hard to store and expensive.

We'd probably need 20m to go round the garden. This is the kind of thing I was thinking but Mumsnetters are full of amazing ideas and I'm wondering if you could suggest anything we might have missed as options.

The problem with these plastic grids is it's impossible to create curved paths which it'd need to be to go round a garden!

Thank you!

I did add an image but it didn't post. Trying again!

Feels like the Internet is broken this morning

How about the foam squares?

Get someone else to level a track round on the grass and returf? Or use topsoil to level a track?

I would suggest some kind of thick-ish matting that you could roll out and then tidy away? Maybe even cheap linoleum that you could cut to make the track?