I came across the following sentence in Wikipedia:
The bitangent lines can be constructed either by constructing the homothetic centers, as described at that article, and then constructing the tangent lines through the homothetic center that is tangent to one circle, by one of the methods described above. The resulting line will then be tangent to the other circle as well. Alternatively, the tangent lines and tangent points can be constructed more directly, as detailed below.
It took me a while to parse it because I was hopelessly looking for the missing or. Leaving alone the fact that this passage is clumsy, is it grammatical according to the rules of standard English?