## ----include = FALSE----------------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#"
)

## ----setup--------------------------------------------------------------------
library(geometries)
library(Rcpp)

## -----------------------------------------------------------------------------

df <- data.frame(
  id1 = c( rep(1,12), rep(2, 12) )
  , id2 = c( rep(1:4, each = 3), rep(1:4, each = 3) )
  , x = 1:24
  , y = 24:1
)

df