I am not a good painter, but because FirebirdSQL it is my favorite database, every time I install it at my customer computer, I think why not have a good logo like as another SQL engines.
You can download files from github/firebird-logo
I am Using www.Inkscape.com to edit svg file
All of pictures under licensee IDPL, you can use it where you want.
By using Gimp 2 to make Beveled picture (Script-Fu->Decor->Add Bevel) with Thickness = 5