diff --git a/src/VTI.f90 b/src/grid/VTI.f90
similarity index 100%
rename from src/VTI.f90
rename to src/grid/VTI.f90
diff --git a/src/base64.f90 b/src/grid/base64.f90
similarity index 100%
rename from src/base64.f90
rename to src/grid/base64.f90
diff --git a/src/zlib.f90 b/src/grid/zlib.f90
similarity index 100%
rename from src/zlib.f90
rename to src/grid/zlib.f90