What is the name of this masonry tool

[GRgrGR55]

 

[Alfredo]

Could it be an edge trowel?

https://webbshop.norfloorkakel.se/v...ktyg/kgc-kantstal-pro-rundad-profil-280x115mm

 

[fahlis]

A kanitz for convex surfaces?

 

[slothy]

I think it's called either whatchmacallit or thingamajig.

 

[Frerider]

Some kind of trowel for concrete/plaster leveling, is the surface concave or is it an optical illusion?