# Diagonal Strip in Square Lattice

The `diagstrip`

element requires a square unit cell and restricts the values of `orient`

to either `45`

or `-45`

. Using this element (rather than a rotated `rectstrip`

) is useful when there are other sheets in the FSS/PSS structure that all share the same square lattice. In this case, the interactions between sheets can be rigorously accounted for using higher-order generalized scattering parameters.

```
using PSSFSS, Plots
sheet = diagstrip(P=5.2, w=0.21, units=mm, Nl=60, Nw=4, orient=45)
p1 = plot(sheet, linecolor=:red, unitcell=true)
p2 = plot(sheet, linecolor=:blue, rep=(4,3))
plot(p1, p2, layout = (1,2), size=(800,400))
```