Figure 2

Diagram showing how a receptor at the location \(\pmb{(i, j)}\) moves towards a bound receptor in its neighborhood. Here, a double box denotes a bound receptor. In (a), the receptor will move to the location \((i-1, j+1)\) if a bound receptor is found at one of the locations shown surrounded by double boxes on the upper left hand corner. In (b), the receptor will move to the location \((i+1, j+1)\) if a bound receptor is found at one of the locations shown surrounded by double boxes in the upper right hand corner. In (c), the receptor will move to \((i+1, j-1)\) if a bound receptor (doubly boxed) is found in the lower right hand corner. In (d), it moves to \((i-1, j-1)\) if a bound receptor (doubly boxed) is found in the lower left hand corner. Finally, in (e) the receptor will move either vertically or horizontally if a bound receptor is found vertically above (or below) it, or to its left (or right), respectively.