Generally a hard or soft edged marking that can have areas that are blurred into the base coat or other markings. This should not be the entire marking! Note how below, there are areas that have hard edges still.
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Markings
These markings have this design rule applied.
Appaloosa
Badger
Banding
Bandit
Barring
Blanket
Blanket Appaloosa
Bumblebee Viper
Choker
Corella
Cracked
Dun
Ember
Eyelet
Fewspot Appaloosa
Fier
GHI Viper
Greying
Heartfire
Hood
Impala
Inkblot
Irish Spotting
Koi
Leopard Appaloosa
Marozi
Mask
Nullified
Nyala
Okapi
Panda
Point
Sabino
Saddle
Seychellois
Snowcap Appaloosa
Stripe
Tail
Tapir
Ticking
Truespot
Underbelly
Viper