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diff --git a/diagrams/join/inner-both.png b/diagrams/join/inner-both.png
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diff --git a/diagrams/join/outer.png b/diagrams/join/outer.png
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diff --git a/diagrams/join/setup.png b/diagrams/join/setup.png
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diff --git a/diagrams/join/setup2.png b/diagrams/join/setup2.png
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diff --git a/oreilly-colours.R b/oreilly-colours.R
new file mode 100644
index 0000000..07798cd
--- /dev/null
+++ b/oreilly-colours.R
@@ -0,0 +1,38 @@
+library(farver)
+library(dplyr, warn.conflicts = FALSE)
+
+oreilly <- tribble(
+  ~ name, ~r, ~g, ~b,
+  "blue", 0, 113, 188,
+  "orange", 247, 147, 30,
+  "red", 193, 39, 45,
+  "green", 0, 146, 68,
+  "yellow", 255, 222, 0,
+  "purple", 153, 0, 204
+)
+oreilly$col <- encode_colour(oreilly[c("r", "g", "b")])
+
+tint <- function(col, tint) {
+  n <- length(tint)
+  col_Lab <- decode_colour(col, to = "Lab")
+  white_Lab <- decode_colour(white, to = "Lab")
+
+  encode_colour(
+    col_Lab[rep(1,n), ] * tint + white_Lab[rep(1,n), ] * (1 - tint),
+    from = "Lab"
+  )
+}
+
+
+tints <- seq(0.1, 1, length.out = 10)
+
+oreilly |>
+  group_by(name) |>
+  summarise(
+    tint = paste0("t", tints * 100),
+    colour = tint(col, tints),
+    .groups = "drop"
+  ) |>
+  tidyr::pivot_wider(names_from = tint, values_from = colour)
+
+scales::show_col(tint(oreilly$col[5], tints))