I am skinning a skewed quad with math I have a quad v1, v2, v3, v4

I have a array (a subdivided patch of vertex) that is sorted so that

[0][0] = v1

[0][8] = v2

[8][8] = v3

[0][8] = v4 

I need to average the vectors to fill in the other locations of the array

FaceData = [ origin, v1, v2, v3, v4]
plane.worldPosition = origin

for x in range(len(array)):
    for y in range(array[x]):
        vertIndex = array[x][y]
        vert.XYZ = ???
        #this is where I need help


edit:
solved problem + visualization
for x in range(8):
    for y in range(8):
        p1 = v1.lerp(v2, x/len[array])
        p2 = v4.lerp(v3, x/len[array])
        p3 = p1.lerp(p2,y/len[array[x])
        this is the point I needed