Do designers steal ideas from each other?

Or ideas are just floating in the air and suddenly we find a lot of similar designs? These thoughts inevitably appear when looking to some of the new designs presented at the last IMM Cologne:

ligne roset TOA, Design: Rémi Bouhaniche, Presented: imm cologne 2015

Thonet 808, Design: Formstelle, Presented: imm cologne 2015 

ligne roset BEAU FIXE 2 seater, Design: Inga Sempé, Presented: imm cologne 2015

Brühl On tour easy chair, Design: Roland Meyer-Brüh, Presented: imm cologne 2015

At least 4 similar designs found in a minute - what do you think?