My attempt is somewhat different. I used separate symbols for each of the Schmidt triggers to make it clearer what’s going on — EasyEDA’s tendency to use a single uninformative rectangle for an IC I think is one of its biggest problems. The output stages for the two sides should be the same (and I think they’re reversed above, but it doesn’t matter), and it looks like some ground connections were missed.
But the output section doesn’t really make much sense to me. Why the two resistors in parallel? What are C9/C12 doing? My guess is the wires from the stripboard to C9/C12 are connected to the wrong ends of those capacitors, and it should be like this:
and then R1 is a pulldown and C9/R4 and R3/C7 are a (fixed) high pass filter and a (fixed) low pass filter which can be mixed in or out with RV7 — so a tone control, and C8/RV8 are a variable high pass filter.
(By the way, above schematic should be labeled “Unverified”, as should the stripboard layout assuming no one here has built it:)
Also, I’ve read that if you try to use all 6 Schmidt triggers in a 40106 for oscillators, you may get crosstalk between them. If you care about that.
(Edit: Incorrect image replaced)