Electronics without Lua

Lua Script component give us many possibilities, but what can we do without using Lua Script? Still many.
I'm not against using Lua, it's just my habit because it's a little inconvenient editing programs on my phone.

Explanation for the sine signal:
This circuit consists of two integrater. Notice the output of the second one is fed back to the first one, inverted. If we define the output as x, we will get a differential equation:
x'' = - x * (k * r)^2
with x(0)=1 , x'(0)=x''(0)=0
where k is a constant, and r is the input.
The solution of that is:
x(t)=sin(k*r*t+p)
t is time, p is phase, and the frequency is r multiplied by k, which is proportional to r.