All horizontal, vertical, and diagonal paths on a grid

grid paths.lua

grid=7 --8x8
paths={}
--horizontal
for y=0,grid do
local p={}
for x=0,grid do
 add(p,{x=x,y=y})
end
add(paths,p)
end
--vertical
for x=0,grid do
local p={}
for y=0,grid do
 add(p,{x=x,y=y})
end
add(paths,p)
end
--diag
for y=-grid,grid do
local p1={}
local p2={}
local p3={}
local p4={}
for a=0,y do
 add(p1,{y=y-a,x=a})
 add(p2,{y=grid-y+a,x=grid-a})
 add(p3,{y=y-a,x=grid-a})
 add(p4,{y=grid-y+a,x=a})
end
add(paths,p1)
add(paths,p2)
add(paths,p3)
add(paths,p4)
end