Various trading strategies

In the following table, we summarize several commonly used trading strategies involving various types of options:

Names	Description	Direction of initial cash-flow	Expectation of future price movement
Bull spread with calls	Buy a call (x1) sell a call (x2) [ x1< x2 ]	Outflow	Rise
Bull spread with puts	Buy a put (x1), sell a put (x2) [ x1< x2 ]	Inflow	Rise
Bear spread with puts	Buy a put (x2), sell a put (x1) [ x1 < x2 ]	Outflow	Fall
Bear spread with calls	Buy a call (x2), sell a call (x1) [x1 < x2 ]	Inflow	Fall
Straddle	Buy a call & sell a put with the same x	Outflow	Rise or fall
Strip	Buy two puts and a call (with the same x)	Outflow	Prob (fall) > prob (rise)
Strap	Buy two calls and one put (with the same x)	Outflow	Prob (rise)> prob(fall)
Strangle	Buy a call (x2) and buy a put (x1) [x1 < x2 ]	Outflow	Rise or fall
Butterfly with calls	Buy two calls (x1,x3) and sell two calls (x2) [x2=(x1+x3)/2]	Outflow...