Examples:
cartography
card
archaeology
archetype
monarchy
legal
loyal
purse
personal
cinema
kinase
car
carpenter
hippopotamus
Mesopotamia
dative
data
date
...
Welsh
dy
←
Breton
da
(cognate)
←
Proto-Celtic
*tou-
(inherited)
←
Welsh
ti
(mention)
←
Irish
do
(cognate)
←
Cornish
dha
(cognate)
→
Breton
da
(cognate)
→
Welsh
ti
(mention)
→
Welsh
di
(mention)
→
Irish
do
(cognate)