I did this flagstone job 3 years ago, I usually only do 1 or 2 a year. I try to just do waterfeatures. The upclose pic was right after being done and the other one was 2 years later. I used 8'' of compacted base and 2'' sand screeded and enviro bond sand for the joints. I love that stuff it looks like mortar and is rock hard, no weeds or anything. I have a homeowner that wants a square cut pattern bluestone patio, but I have never done that and it looks like it would be really hard to do, I think im going to pass. How hard is it to do sawn square pattren versus the way I generally do them? Yes I did that small pondless waterfall in the pic.