Response to an alien attack proposal

Fermi´s paradox offers an endless questions about alien existence, bla, bla… just philosophical entertainment. But the important point is: Are we ready for an alien attack? Probably they will fumigate us as insects. Our weapons have nothing to do. I propose a desperate and low chances of success solution: show them we are able to do great things. For example, create a planet size copy of Picasso´s painting "Las señoritas de Avignon". Each human should participate with a 190 m side square part, including babys and clumsy people. Even if aliens don´t perceive it, I guess some part of the mortal ray attack could be stopped by the painting (dense canvas preferred). Well, in the worst of the cases, if mankind is finally destroyed, we could be proud to create such a nonsense final artwork. Absurd and epic end, yeah!