Given:
r[t_] := {Sin[t], Sin[2 t]}
uT[t_] := Simplify[r'[t]/Norm[r'[t]], t \[Element] Reals]
Animate[Show[ParametricPlot[{r[t]}, {t, -\[Pi], \[Pi]}],
Graphics[{{Line[{{Sin[t], Sin[2 t]}, {-(Cos[t]/Sqrt[Cos[t]^2 + 4 Cos[2 t]^2]) +
Sin[t], -((2 Cos[2 t])/Sqrt[Cos[t]^2 + 4 Cos[2 t]^2]) +
Sin[2 t]}}]}}], PlotRange -> {{-2, 2}, {-2, 2}}], {t, 0, 2 \[Pi]},
AnimationRunning -> False]
How do I replace the line with a triangle, to follow the curve as the picture below shows?