Don't want to sound like a killjoy but those seem absolutely pointless. If you made one so small it would fit in a sole of a shoe I'd reconsider but in their cu

Don't want to sound like a killjoy but those seem absolutely pointless. If you made one so small it would fit in a sole of a shoe I'd reconsider but in their current form they're just as inconvenient when not in use as a bike and infinitely less useful when riding.