begin name
shenorr1
end name

begin reactions
r1 {1.0}$EXTERNAL = {1.0}Y
r2 {1.0}Y = {1.0}$EXTERNAL
r3 {1.0}$EXTERNAL = {1.0}Z
r4 {1.0}Z = {1.0}$EXTERNAL
end reactions

begin rate equations
r1 = F[X, r1Ty]
r2 = r2a*Y[t]
r3 = F[X, r3Ty]*F[Y[t], r3Tz]
r4 = r4a*Z[t]
end rate equations

begin parameters
X = 0.0
r1Ty = 0.5
r2a = 1.0
r3Ty = 0.5
r3Tz = 0.5
r4a = 1.0
cell = 1.0
end parameters

begin initial conditions
Y[0] = Yi
Z[0] = Zi
end initial conditions

begin initial values
Yi = 0.0
Zi = 0.0
end initial values

begin assignment rules
end assignment rules

begin function definitions
F[X_,T_] := Piecewise[{{1, X >= T}}, 0]
end function definitions

begin events
e3 = (t >= 10, {X -> 1}, 0)
e4 = (t >= 15, {X -> 0}, 0)
e2 = (t >= 3.5, {X -> 0}, 0)
e1 = (t >= 3, {X -> 1}, 0)
end events

begin process annotations
end process annotations

begin species annotations
end species annotations

begin units
end units