Between the two-hour season finale for Marvel’s Agents of SHIELD and the penultimate episode of The Flash, this Tuesday evening has shaped up nicely.  The CW has taken an interesting approach to its teasers: short teaser after the current episode and then a double-sized trailer a few days later.  Here’s the one-minute preview of Tuesday’s episode of The Flash.  I kind of knew that putting all those villains in one place was a bad idea . . .