--- a/README.markdown Thu Feb 06 00:02:24 2020 -0500
+++ b/README.markdown Sat Feb 08 11:35:59 2020 -0500
@@ -482,3 +482,77 @@
Refactored the `Makefile` and added in all the alignment stuff. Wrote up the
weekly report far too late.
+
+## 2020-02-08
+
+Decided to try using gnuplot to do the graphing exercises in the Campbell
+Biology textbook, to combine the things I've been reading lately.
+
+The first exercise I did was from chapter 9. Data:
+
+ Low 4.3
+ Normal 4.8
+ Elevated 8.7
+
+Gnuplot file:
+
+ set title "{/:Bold*1.5 Thyroid Hormome Levels and Oxygen Consumption}"
+ set xlabel "Thyroid Hormone Level"
+ set ylabel "Oxygen Consumption Rate [nmol O_2 / (min * mg cells)]"
+
+ unset key
+ set boxwidth 0.8
+
+ plot [][0:10] "bio/thyroid" u 0:2:xtic(1) w boxes fillstyle solid fc rgb "black"
+
+That was pretty simple. Then I went back to a previous chapter. Data:
+
+ # Time (min) Concentration of inorganic Phosphate (μmol/mL)
+ 0 0
+ 5 10
+ 10 90
+ 15 180
+ 20 270
+ 25 330
+ 30 355
+ 35 355
+ 40 355
+
+Gnuplot file:
+
+ set title "{/:Bold*1.3 Glucose-6-Phosphate Activity in Isolated Liver Cells}"
+ set xlabel "Time (minutes)"
+ set ylabel "Concentration of ℗_i (μmol/mL)"
+
+ set xtics format "%h min"
+
+ unset key
+
+ set grid xtics ytics
+
+ set lmargin 12
+ set rmargin 6
+
+ plot [0:45][0:400] "liver-glucose" w lines linewidth 2
+
+This one was a little trickier. I was trying to play around in the gnuplot
+REPL, but pasting the Unicode characters was producing garbage at the gnuplot
+command line. Pasting into a normal terminal/fish shell worked fine. After
+much flailing I tracked down the problem to gnuplot itself:
+
+* Gnuplot uses one of several different libraries to handle readline-like
+ editing: `libeditline`, GNU `readline`, and some others (I think).
+* The library it uses is specified as an argument to `./configure` and linked in
+ at compile time.
+* `libeditline` does not handle UTF-8 input correctly in this, the year of our
+ Lord, 2020.
+* GNU `readline` *does* handle UTF-8 input correctly.
+* Unfortunately, `readline` is GPL-licensed, which is incompatible with
+ gnuplot's license.
+* Debian (and Ubuntu) therefore link gnuplot with the broken `libeditline`,
+ rather than linking it to `libreadline` and violating the GPL.
+* As far as I can tell, there's no way to simply disable all line editing in
+ gnuplot so it can be wrapped with `rlwrap` or something.
+
+At this point I just gave up on using Unicode at the REPL and created `.gp`
+files that I then `load`. The GPL strikes again.