```r
library(data.table)
dt1 <- data.table(expand.grid(pre = c("dotmotion-update", "update-dotmotion"),
post = c("dotmotion-update", "update-dotmotion"),
colours_hex = c("blue-green-orange-red",
"blue-orange-green-red",
"blue-red-orange-green",
"green-orange-blue-red",
"green-red-blue-orange",
"orange-red-blue-green")))
```