for suit <- suits do
	suit
end

# nested list happens.
cards = for value <- values do
	for suit <- suits do
		"#{value} of #{suit}"
	end
end

### output ###
[[..,,,.,,.,,],[...],[...],...]

### Sol.1 Use flatten
List.flatten(cards)

### Sol.2 (recommended!)
for suit <- suits, value<- values do
	"#{value} of #{suit}"
end