diff --git a/data/book/02/ohz.R b/data/book/02/ohz.R
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+++ b/data/book/02/ohz.R
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+library(aqp)
+
+set.seed(456)
+
+d <- list(
+  id = "P",
+  name = c(c("Oe", "Oa", "A", "Cg1", "Cg2")),
+  depths = c(28, 30, 50, 100, 250),
+  soil_color = c("10YR 2/2", "10YR 2/1", "7.5YR 2.5/1", "10Y 4/1", "2.5Y 5/1"),
+  soc = c(30, 32, 4, 0.8, 0.5),
+  bdy = aqp::hzDistinctnessCodeToOffset(c(
+    "gradual", "gradual", "clear", "diffuse", "clear"
+  ))
+)
+
+ohz <- aqp::quickSPC(d, ) |> 
+  aqp::perturb(n = 10, boundary.attr = "bdy") |> 
+  trunc(0, 200)
+
+ohz$soc <- pmax(0.1, jitter(ohz$soc, abs(log10(ohz$soc) * (ohz$bottom - ohz$top))))
+ohz$soc[runif(nrow(ohz)) > 0.97] <- NA
+
+plot(ohz)
+plot(ohz, color='soc')
+
+save(ohz, file ="../data/book/02/ohz.rda")
diff --git a/data/book/02/ohz.rda b/data/book/02/ohz.rda
new file mode 100644
index 00000000..f684034e
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