1. Draw a straight line. 2. Place point "a" at the beginning of the line.
3. Place point "b" on the line after a distance of 10 from "a".
4. Place point "c" after a distance of 10 from "b"
5. Place point "d" after a distance of 9.5 from "c".
6. Place point "e" after a distance of 10 from "d".
7. Place point "f" after a distance of 2 from "e".

Now imagine that this line is a road and a car parking before point "a" begins to move at a constant speed. Once it reaches point "a", its speed begins to deaccelerate according to a function.

Assume that the time required to travel from "a" to "b" was X.

The car passes point "b" and continues deaccelerating according to the function. However, the time to travel from "b" to "c" is unspecified.

The car continues past point "c" and eventually reaches "d" in X time.

The travel time from "d" to "e" is unspecified.

The travel time from "e" to "f" is still X.

Assuming that the car never accelerates and continues to deaccelerate in the distances where travel time is not specified: what is the deacceleration function (if possible) such that the car could maintain the travel time of X across the specified distances between "a" and "b", "c" and "d", and "e" and "f"?