== idle t=0 is rest for all cells ==
idle_t0_rest true
== idle mid-phase deforms, bounded ==
idle_mid_moves true idle_bounded true
== select pop envelope ==
select_start_rest true select_end_rest true select_mid_pops true
== land squash envelope ==
land_start_rest true land_end_rest true land_mid_wobbles true
== clear pop envelope ==
clear_start_full true clear_end_gone true clear_overshoots true
== gem motion land bookkeeping ==
motion_init true motion_no_land true motion_fresh_land true
ok: per-gem animation rests at t=0 and stays bounded