Galilean Transformation

Needs["Graphics`Animation`"];

Ruler[x_, t_] := 
        Graphics[{Line[{{x, t}, {x, t + 0.1}}], 
            Line[{{x, t + 0.2}, {x, t + 0.3}}], 
            Line[{{x, t + 0.4}, {x, t + 0.5}}], 
            Line[{{x, t + 0.6}, {x, t + 0.7}}], 
            Line[{{x, t + 0.8}, {x, t + 0.9}}]}];

Event[x_, t_, z_, t0_] := 
      Graphics[{PointSize[0.05], 
          If[t == t0, Point[{x, z}], {}]}]

Animate[
      Show[Ruler[0, 0], Ruler[0.05, t], Event[0.025, t, 0.5, 0.2], 
        Event[0.025, t, 0.6, 0.4], PlotRange -> {{0, 1}, {0, 1}}], {t, 
        0, 1, 0.01}]

Animate[
      Show[Ruler[0, 0], Ruler[0.05, t], Event[0.025, t, 0.5 + 0.5  t, t], 
        PlotRange -> {{0, 1}, {0, 1}}], {t, 0, 1, 0.01}]