Seq uses the elements type alignof(T) to determine alignment. You can use the [align](https://nim-lang.github.io/Nim/manual.html#implementation-specific-pragmas-align-pragma) pragma to influence the resulting alignment. Warning: putting align in the type definition like `type Foo {.align: 32.}` doesn't work. It needs to be a field or a variable.
I have a long time since I [experimented](https://github.com/planetis-m/dumpster/blob/master/vectorisation/alphatensor4x4.nim) with explicit vectorization, but from what I can remember, you need to set each element individually, and they are reversed. Also compile with AddressSanitizer support `-t:"-fsanitize=address,undefined" -l:"-fsanitize=address,undefined" -d:nosignalhandler`. It's your best bet to figure out what's going on.
