GridapEmbedded 
Embedded finite element methods, level set surface descriptions and constructive solid geometry.
Installation
# Type ] to enter package mode
pkg> add GridapEmbedded Examples
Constructive Solid Geometry (CSG)
julia> include("examples/PoissonCSGCutFEM/PoissonCSGCutFEM.jl")
julia> PoissonCSGCutFEM.main(n=40,outputfile="results1")
left picture by wikipedia.org
julia> include("examples/StokesTubeWithObstacleCutFEM/StokesTubeWithObstacleCutFEM.jl")
julia> StokesTubeWithObstacleCutFEM.main(n=10,outputfile="results2")
Bimaterial problems
julia> include("examples/BimaterialLinElastCutFEM/BimaterialLinElastCutFEM.jl")
julia> BimaterialLinElastCutFEM.main(n=4,outputfile="results3")