Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could mess mess you could mess mess he could mess mess we could mess mess you could mess mess they could mess mess
V-ing form
I could be mess messing you could be mess messing he could be mess messing we could be mess messing you could be mess messing they could be mess messing
Perfect
I could have mess messed you could have mess messed he could have mess messed we could have mess messed you could have mess messed they could have mess messed
V-ing perfect
I could have been mess messing you could have been mess messing he could have been mess messing we could have been mess messing you could have been mess messing they could have been mess messing
Negation
Simple form
I could not mess mess you could not mess mess he could not mess mess we could not mess mess you could not mess mess they could not mess mess
V-ing form
I could not be mess messing you could not be mess messing he could not be mess messing we could not be mess messing you could not be mess messing they could not be mess messing
Perfect
I could not have mess messed you could not have mess messed he could not have mess messed we could not have mess messed you could not have mess messed they could not have mess messed
V-ing perfect
I could not have been mess messing you could not have been mess messing he could not have been mess messing we could not have been mess messing you could not have been mess messing they could not have been mess messing
Interrogative form
Simple form
could I mess mess? could you mess mess? could he mess mess? could we mess mess? could you mess mess? could they mess mess?
V-ing form
could I be mess messing? could you be mess messing? could he be mess messing? could we be mess messing? could you be mess messing? could they be mess messing?
Perfect
could I have mess messed? could you have mess messed? could he have mess messed? could we have mess messed? could you have mess messed? could they have mess messed?
V-ing perfect
could I have been mess messing? could you have been mess messing? could he have been mess messing? could we have been mess messing? could you have been mess messing? could they have been mess messing?
Interro-negative form
Simple form
could I not mess mess? could you not mess mess? could he not mess mess? could we not mess mess? could you not mess mess? could they not mess mess?
V-ing form
could I not be mess messing? could you not be mess messing? could he not be mess messing? could we not be mess messing? could you not be mess messing? could they not be mess messing?
Perfect
could I not have mess messed? could you not have mess messed? could he not have mess messed? could we not have mess messed? could you not have mess messed? could they not have mess messed?
V-ing perfect
could I not have been mess messing? could you not have been mess messing? could he not have been mess messing? could we not have been mess messing? could you not have been mess messing? could they not have been mess messing?