On cozumel, how do you know which pictures to count to get the coordinates?

Answer 1

To solve this puzzle, you need to find repeating patterns on the wall. If you consider the wall a 31 across and 20 down you get the following coordinates to follow from left to right forming a serpent using the head icons.
I will give the coord with column, row.

Series 1
1,6
Series 2 (all made up of the same head)
2,6
3,6
3,7
3,8
3,9
4,9
4,8
5,8
Series 3
6,8
Series 4
6,9
7,9
7,10
7,11
8,11
8,10
9, 10
10,10
Series 5
10,11
10,12
11,12
11,13
11,14
12,14
12,13
13,13
13,12
13,11
13,10
14,10
14,11
15,11
Series 6
15,12
15,13
16,13
17,13
17,12
18,12
Series 7
18,13
18,14
18,15
19,15
20,15
Series 8
20,14
Series 9
20,13
20,12
20,11
21,11
21,10
22,10
22,9
23,9
Series 10
23,10
24, 10
24, 11
24, 12
25, 12
25, 11
26, 11
26, 10
27, 10
28, 10
28,11
28, 12
27, 12
27, 13
27, 14
28, 14
28, 15
29, 15
29, 14
30, 14
30, 13
30, 12
31, 12

Now if you count the number in each section you get
Series 1 = 1
" 2 = 8
" 3 = 1
" 4 = 8
" 5 = 14
" 6 = 6
" 7 = 5
" 8 = 1
" 9 = 8
" 10 = 23

From these numbers we can derive the coordinates.

The first four coordinates are the first four series numbers:
1818

The fifth series number refers to the direction N (n=14, see below)

The next coords are 6518

The last series number refers to the direction W (w=23)

Therefore,
1818N6518W

a=1
b=2
c=3
d=4
e=5
f=6
g=7
h=8
i=9
j=10
k=11
l=12
m=13
n=14
o=15
p=16
q=17
r=18
s=19
t=20
u=21
v=22
w=23
x=24
y=25
z=26