* Stuff left to do

** DONE Detect when player leaves the road
** TODO Add non-player cars onto the road
*** DONE Add constant van on one lane
*** DONE Put van on random lane
*** DONE Add multiple vehicles on different lanes
*** TODO Ensure vehicles don't overlap

Possible algorithm:

#+begin_src
when car goes off-screen
go through all lanes
if lane has space, roll a die
if lucky
    pick an inactive car
    activate that car on the lane
#+end_src

What happens if there are no cars on screen!?
 => Force it?

** TODO Detect collision with other vehicles
** TODO Add weapon to player car
*** TODO Make weapon a power-up
*** TODO Make weapon use limited (bullet? time?)
** TODO Add graphical speedometer (look at knight rider)
** TODO Improve visuals
** TODO Add start menu
** DONE Add music
** TODO Add sound effects