*To draw a straight line from any point to any point.*

A postulate, to quote from dictionary.com is something taken as self-evident or assumed without proof as a basis for reasoning. And according to Euclid, nothing can be more self-evident than the fact that given two points, one can draw a straight line segment joining them.

Now, it is also obviously self-evident that there is exactly one such line joining two given points, i.e. that there is a unique line joining any two points.

However Euclid does not mention the uniqueness, though he seems to assume it in the subsequent proofs .. So probably a more accurate first postulate would be

*To draw a straight line (which will be unique) from any point to any point.*

**The Processing code**

int time1 = 500; int time2 = 2500; PFont f; void setup() { size(600, 120); smooth(); f = createFont("Arial",20,true); } void draw() { int currentTime = millis(); background(204); if (currentTime > time2) { ellipse(100,60,10,10); text("A",95,90); fill(0); ellipse(500,60,10,10); text("B",495,90); line(100,60,500,60); } else if (currentTime > time1) { textFont(f,20); fill(0); ellipse(100,60,10,10); text("A",95,90); fill(0); ellipse(500,60,10,10); text("B",495,90);} }