"""

```
image(x,sides)
```

Move coordinates to minimum perioddic image.

"""
image(x,sides) = image_one.(x,sides)

# Translate a single coordinate according to periodic conditions
function image_one(x,side)
  xmod = mod(x,side)
  if xmod <= -side/2
    return xmod + side
  elseif xmod > side/2
    return xmod - side
  else
    return xmod
  end
end

