Table 2.

List of possible grid maps and properties of these grid maps given the total number of units participating in a trajectory-coding sequence in a rectangular environment. For each individual unit’s grid map that has a non-zero angle to a border, a reflection or 90°-rotation and reflection up to relabeling of the units exist, and these additional possibilies are not included in this list.

# cells	Repeat lengthsa	Lattice type	Smallest angle to a border of a rectangular environmentb
7	7, 7, 7	Hexagonal	10.9°
8	4, 8, 8	Centered rectangular	0°
	4, 8, 8	Oblique	10.9°
9	3, 3, 3	Hexagonal	0°
	3, 9, 9	Oblique	10.9°
	3, 9, 9	Oblique	13.9°
	3, 9, 9	Oblique	16.1°
10	5, 10, 10	Oblique	0°
	5, 10, 10	Oblique	10.9°
	5, 10, 10	Oblique	16.1°
11	11, 11, 11	Oblique	6.6°
	11, 11, 11	Oblique	10.9°
	11, 11, 11	Oblique	16.1°
12	6, 6, 6	Hexagonal	0°
	3, 12, 12	Rectangular	0°
	3, 12, 12	Rectangular	10.9°
	3, 4, 12	Oblique	0°
	3, 4, 12	Oblique	13.9°
	4, 6, 12	Oblique	0°
	4, 6, 12	Oblique	6.6°
	4, 6, 12	Oblique	23.4°

^aRepeat lengths across the three major axes of the hexagonal lattice structure of densely packed firing fields.

^bThe smallest angle to a border of a rectangular environment assumes that one sequence of units is arranged in parallel to one wall.