Another channel indicator made of standard deviation of a 2 centered linear regression of the 300 last periods of high and low price values (by default).
//Parameters :
// Len = 300
z1 = linearregression[Len](high)
z2 = linearregression[Len](low)
z2s = -std[len](low)+z2
z1s = std[len](high)+z1
RETURN z1 coloured(255,250,240), z2 coloured(255,250,240), z1s as "high LR dev", z2s as "low LR dev"