A walk-along circular saw plywood ripper. I put a 4 foot handle on a
circular saw. It was attached to a plywood plate and a right angle
edge, that positions the blade exactly 10" from a ripping guide.

I can rip plywood sitting on 2x4's on the floor by just walking along
guiding the circular saw against the guide. Just like using a lawn
edger.

Very accurate, safe, and convenient.