lxl + lyl = 1
if x = 0, then y = 1,
and if y = 0, then x = 1.
So (0,1) and (1,0) are definitely points.
Also, we can also do the same for:
if x = 0, then y= -1 as well since we have the absolute value sign,
and if y = 0, then x = -1 as well since we have the absolute sign.
So, we now have 4 main points (0,1), (1,0), (0, -1), & (-1,0).
Now, we know x or y cannot be greater than 1 since lxl + lyl must be equal to 1 [if x = 2, then there would be no value for y that would satisfy the equation].
Furthermore, we notice that 0.5 + 0.5 also equals 1 so we get more points: (0.5, 0.5), (-0.5, 0.5), (-0.5, -0.5), & (0.5, -0.5).
We now have 8 points and if you connect them together, you get a square.
So, these 8 points create a square with sides of sqrt(2).