Lighthouses

There's a job to do!

You have to place the lighthouses in the area... but beware! The lighthouse keepers are very grumpy and do not want its lighthouse is illuminated by another!

Each lighthouse illuminates the area corresponding to the row, column and diagonal on the islet where it is located!

Will you be able to illuminate the entire area without interfering with each another lighthouse?

And above all... be able to find all the possible combinations to do it?