S at t 2

S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2
S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2
S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2S at t 2