Minor: speed -> angles

Author: timhutton

README.md

@@ -17,6 +17,6 @@ History: (please help fill in the gaps!)
 TO-DO list:
 - Is the 1+1 approach used (the parabolic axes in the inertial frame drawn on the right) in any way correct or rigorous?
 - Can we extend to 1+1 with a varying gravitational field (e.g. from Earth's surface to Moon's orbit)? Or with a point mass on the 1D line (a black hole)?
-- Can we extend to 2+1 with a constant gravitational field? Here the parabolas can be of different shapes representing objects travelling at different speeds.
+- Can we extend to 2+1 with a constant gravitational field? Here the parabolas can be of different shapes representing objects launched at different angles.
 - Can we extend to 2+1 with a point mass? Perhaps by considering a single geodesic (e.g. an elliptic orbit) as a straight line and drawing the rest of the universe as a (possibly very strange) distorted grid around that geodesic?
 - In which of the above can we find a warping of spacetime such that *all* inertial objects move along straight lines? (As is true with the current constant-gravity 1+1 model.)