Enormous concrete saw. 6:48 video:
https://www.youtube.com/watch?v=7ZtDZGiIpG0
Previously:
https://www.homemadetools.net/forum/...205#post126399
https://www.homemadetools.net/forum/...080#post125690
https://www.homemadetools.net/forum/...349#post110233
https://www.homemadetools.net/forum/...449#post122466
https://www.homemadetools.net/forum/...088#post120617
https://www.homemadetools.net/forum/...3100#post98061