The center of the image has already been explained above. For the rest, you need to see examples of the five principal functions of kaš. The most central seems to be as an irrealis indefinite determiner, as in:
جا كاش واحد؟However, it can also be used existentially in questions, as in:
ja kaš waħəd? came any one? "Did anyone come?"
كاش حليب؟And, of course, it forms the second half of the extremely frequent negative existential "there is no":
kaš ħlib? any milk? "Is there any milk?"
ماكاش الزهرIn combination with the complementiser ma ما, it yields another two rather surprising constructions:
makaš əz-zhəṛ NegExist the-luck "There is no luck."
كاش ما شريت؟
kaš ma šri-t? any that buy-2Sg? "Did you buy anything?"
كاش ما جا؟For full details of how Algerian Arabic managed to produce all these functions by combining an existential marker and a quantifier, you'll have to read the article!
kaš ma ja? any that came? "Did he come (at all, by any chance)?"
A rather similar grammaticalization seems to have taken place in Chinese for yŏu 有; can you think of any other comparable cases?