After living with lots of different Indians - and I am not being unPC here, I do mean Indians, as in from India - and having lots of Indian friends in college, I learned a couple of things...
(2) Every Indian cook has his or her personal blend of those spices. And curries also vary by geography. For example curries in Kerala, one of the most southern Indian states, include tamarind while Bengali curries utilize mustard seed and mustard oil.
(3) Curries can be red, yellow, or green. I still don't have a definitive answer about what makes a curry red while another is yellow. But I suspect, based on curry-fact number two, that the human element makes the difference. If someone uses more turmeric in the curry spice mix, it will be more yellow, more paprika means more red. Sounds plausible, doesn't it?
(4) There are also wet curries and dry curries. This simply has to do with how much liquid is used to begin and how long the dish is cooked.
I now have one of those hammered spice tins of my own and I enjoy playing with different combinations of flavors. But for a mid-week dinner, sometimes I cheat and use a pre-blended spice packet. Tonight I used a Green Curry Blend from CostPlus World Market. Curry in a hurry.
I browned chicken with minced garlic. Once the chicken was cooked, I added the green curry spice blend, a can of coconut milk, and a splash of beet juice. Next I added cooked white kidney beans and cubes of zucchini. And just before serving I added six cups of fresh spinach and stirred till wilted. I served this over leftover red quinoa pilaf.