to get a MDS code from a hyperoval in a projective plane explain how we can get a MDS code of length q+2 and dimension q-1 from a hyperoval
in a projective plane PG2(q) with q a power of 2?
HINT:a hyperoval Q is a set of q+2 points such that no three points in Q are collinear.
you are expected to get a [q+2,q-1,4] binary code from this.take points,one dimensional 
subspaces and blocks as the lines 2-dimensional subspaces

As an addition to the answer of Jyrki Lahtonen:
The standard way to get projective coordinates of the points of a hyperoval over $\mathbb F_q$ is to take the vectors $[1 : t : t^2]$ with $t\in\mathbb F_q$ together with $[0 : 1 : 0]$ and $[0 : 0 : 1]$.
Placing these vectors into the columns of a matrix, in the example $\mathbb F_4 = \{0,1,a,a^2\}$ (with $a^2 + a + 1 = 0$) a possible check matrix of a $[6,3,4]$ MDS code is 
$$
\begin{pmatrix}
1 & 0 & 0 & 1 & 1 & 1 \\
0 & 1 & 0 & 1 & a & a^2 \\
0 & 0 & 1 & 1 & a^2 & a
\end{pmatrix}
$$
This specific code is also called Hexacode.
