from the same random seed. This is quite possible the cause of stitching
failures. From the File::Temp man page:

"If you are forking many processes in parallel that are all creating
 temporary files, you may need to reset the random number seed using
 srand(EXPR) in each child else all the children will attempt to walk
 through the same set of random file names and may well cause
 themselves to give up if they exceed the number of retry attempts."