This puzzle consists of a series of number pyramids with some squares being colored differently than the other squares. We begin by filling the white squares using standard number pyramid rules, where each square is the sum of the two squares below it.






61 











33 
28 









21 
12 
16 







20 
1 
11 
5 





















213 










52 
161 








146 
94 
67 






84 
62 
32 
35 




41 
43 
19 
13 
22 
5 

16 
25 
18 
1 


4 





























53 

70 









34 
36 





28 

25 
9 
27 



13 
15 


12 
15 

After filling some of the white squares using the standard rules we notice that the purple squares have numbers that are smaller than the sum of the numbers below them. Using this we deduce that the purple squares represent subtracting the number below and to the right from the number below and to the left. (Note that one of the purple squares has a negative number, which invalidates the possibility that the purple squares are taking the absolute difference.)






61 











33 
28 









21 
12 
16 







20 
1 
11 
5 





















213 










52 
161 








146 
94 
67 






84 
62 
32 
35 




41 
43 
19 
13 
22 
5 

16 
25 
18 
1 
13 
9 
4 





























53 

70 









34 
36 





28 

25 
9 
27 



13 
15 
4 
21 
12 
15 

Continuing to fill in the squares we notice that the numbers in the green squares are much bigger than the sum of the two numbers below them. Using this fact we deduce that the green squares represent multiplying the two numbers below. Assuming that the base must be filled with positive integers, we can now fill all of the squares.






61 











33 
28 









21 
12 
16 







20 
1 
11 
5 









162 











213 
−51 









52 
161 
212 







146 
94 
67 
145 





84 
62 
32 
35 
110 



41 
43 
19 
13 
22 
5 

16 
25 
18 
1 
13 
9 
4 






4844 











173 
28 









180 
−7 
35 







20 
9 
16 
19 









2503 











1243 
1260 









53 
1190 
70 







88 
35 
34 
36 





28 
60 
25 
9 
27 



13 
15 
4 
21 
12 
15 







3756 











4365 
609 









3888 
477 
132 







432 
9 
53 
79 





460 
28 
19 
34 
45 



20 
23 
5 
14 
20 
25 







5425 











217 
25 









203 
14 
11 







192 
11 
3 
8 





16 
12 
1 
3 
5 








104 











60 
44 









3 
20 
24 







2 
1 
19 
5 



Having filled all the pyramids we now read the bases using A1Z26 and get the cluephrase TAKE PYRAMID TIPS MODULO TWENTY PLACE BASE. We now take the number in the top square of each pyramid modulo twenty, insert them into the base of the final image and reapply the previously used rules.

3 
8 
1 
19 
11 
1 

1 
2 
4 
3 
16 
5 
4 
Reading the top row we get the answer CHASKA.