With 'Reach', Williams Mackrell is scrawling with a crayon directly on the wall but the just as compelling aspect to notice is taking place at the bottom right of the living picture.
The medium states 'Crayon and cable tie'. Williams's left ankle is shackled. The artist's mark-making benefits from the restriction -he is drawing restrained.
It gives him a degree of balance and sets a limitation to his reach. The red crayola makes it more bodily than charchoal or graphite would.