Figure $2$ shows two identical sound sources located at points $1$ and $2,$ separated by $\backslash ($ D$=\backslash )1\mathrm{.}75$ m $.$ The sound waves have a wavelength of $0\mathrm{.}5$ m and propagate isotropically.

When a sound detector moves along the circular trajectory shown in the figure, how many positions of constructive interference occur? Additionally, how many positions of destructive interference occur? Assume that the center of the circle is located midway between points $1$ and $2.$