Assuming the springs are identical, the potential energy associated with each spring will be $$ U = \frac{1}{2} k (\ell_0 - \ell(x,y))^2 $$ where $\ell_0$ is the uncompressed length of the springs and $\ell(x,y)$ is the length of the spring when the mass is at the position $(x,y)$. This latter function can be found via straightforward geometry.

Note that the resulting functional form for the potential energy is not particularly "clean" unless $\ell_0 = 0$.

Assuming the springs are identical, the potential energy associated with each spring will be $$ U = \frac{1}{2} k (\ell(x,y) - \ell_0)^2 $$ where $\ell_0$ is the uncompressed length of the springs and $\ell(x,y)$ is the length of the spring when the mass is at the position $(x,y)$. This latter function can be found via straightforward geometry.

Note that the resulting functional form for the potential energy is not particularly "clean" unless $\ell_0 = 0$.

The potential energy associated with each spring will be $$ U = \frac{1}{2} k (\ell_0 - \ell(x,y))^2 $$ where $\ell_0$ is the uncompressed length of the springs and $\ell(x,y)$ is the length of the spring when the mass is at the position $(x,y)$. This latter function can be found via straightforward geometry.

Note that the resulting potential energy is not particularly "clean".

Assuming the springs are identical, the potential energy associated with each spring will be $$ U = \frac{1}{2} k (\ell_0 - \ell(x,y))^2 $$ where $\ell_0$ is the uncompressed length of the springs and $\ell(x,y)$ is the length of the spring when the mass is at the position $(x,y)$. This latter function can be found via straightforward geometry.

Note that the resulting functional form for the potential energy is not particularly "clean" unless $\ell_0 = 0$.