Stable gas plummer sphere test for Bridge. The test consists of evolving a gas Plummer sphere for 10 N-body times where the hydro forces and self gravity are split over two instances of Fi using Bridge. Left panels show the deviation of the potential (yellow dashed), kinetic (green dotted), thermal (blue dash-dotted) and total energy (red drawn) as a function of time (initial energy values are –0.5, 0, 0.25 and –0.25 respectively). Right panels show the gas density profiles at 10 equally spaced times. Upper panels show results for N = 10⁴ particles, while lower panels are for N = 10⁵.