Ch. 17: fix diagrams and embed them in the text

- Swap the ordering to match the order in the text (concurrent is first,
  at least for now).
- Make them go left-to-right instead of top-to-bottom for compactness in
  the text.
- Fix rendering issues resulting from the VS Code extension doing things
  that normal `dot` does not, for who knows what reasons.

dot/trpl17-01.dot

@@ -1,21 +1,44 @@
 digraph {
    dpi = 300.0;
 
-   Parallel [label = "Parallel";shape = "plaintext";];
-   rankdir = "TB";
-   splines = false;
-   cluster = true;
+   rankdir = "LR";
+
+   // makes ordering between subgraphs work
+   newrank = true;
 
    node [shape = diamond;];
 
-   subgraph cluster_ColleagueA {
-      newrank = true;
-      label = "Task 1";
-      A1 -> A2 -> A3 -> A4;
+   subgraph cluster_task_a {
+      label = "Task A";
+
+      A1;
+      A2;
+      A3;
+      A4;
+
+      A1 -> A2 -> A3 -> A4 -> A0 [style = invis;];
+
+      // for vertical alignment purposes only
+      A0 [style = invis;];
+
+      // Makes the heights line up between the boxes.
+      A4 -> A0 [style = invis;];
    }
 
-   subgraph cluster_ColleagueB {
-      label = "Task 2";
-      B1 -> B2 -> B3;
+   subgraph cluster_task_b {
+      label = "Task B";
+
+      // for horizontal alignment purposes only
+      // newrank = true;
+
+      B0 [style = invis;];
+
+      B1;
+      B2;
+      B3;
+
+      B0 -> B1 -> B2 -> B3 [style = invis;];
    }
+
+   A1 -> B1 -> A2 -> B2 -> A3 -> A4 -> B3;
 }

dot/trpl17-02.dot

@@ -1,46 +1,20 @@
 digraph {
    dpi = 300.0;
 
-   Concurrent [label = "Concurrent";shape = "plaintext";];
-   rankdir = "TB";
+   rankdir = "LR";
    splines = false;
    cluster = true;
 
    node [shape = diamond;];
 
-   subgraph cluster_task_a {
-      label = "Task A";
-
-      // makes ordering between subgraphs work
+   subgraph cluster_ColleagueA {
       newrank = true;
-
-      A1;
-      A2;
-      A3;
-      A4;
-
-      // for vertical alignment purposes only
-      A0 [style = invis;];
-
-      edge [style = invis;];
+      label = "Task 1";
+      A1 -> A2 -> A3 -> A4;
    }
 
-   subgraph cluster_task_b {
-      label = "Task B";
-      cluster = true;
-
-      // for vertical alignment purposes only
-      newrank = true;
-
-      B0 [style = invis;];
-
-      B1;
-      B2;
-      B3;
+   subgraph cluster_ColleagueB {
+      label = "Task 2";
+      B1 -> B2 -> B3;
    }
-
-   A1 -> B1 -> A2 -> B2 -> A3 -> A4 -> B3;
-
-   // Makes the heights line up between the boxes.
-   A4 -> A0 [style = invis;];
 }

src/ch17-00-async-await.md

@@ -81,10 +81,26 @@ to the other. You are just one person, and you cannot make progress on both
 tasks at the exact same time—but you can multi-task, making progress on multiple
 tasks by switching between them.
 
+<figure>
+
+<img alt="Concurrent work flow" src="img/trpl17-01.svg" class="center" />
+
+<figcaption>Figure 17-1: A concurrent workflow, switching between Task A and Task B</figcaption>
+
+</figure>
+
 When you agree to split up a group of tasks between the people on the team, with
 each person taking one task and working on it alone, this is *parallelism*. Each
 person on the team can make progress at the exact same time.
 
+<figure>
+
+<img alt="Concurrent work flow" src="img/trpl17-02.svg" class="center" />
+
+<figcaption>Figure 17-2: A parallel workflow, where work happens on Task A and Task B independently</figcaption>
+
+</figure>
+
 With both of these situations, you might have to coordinate between different
 tasks. Maybe you *thought* the task that one person was working on was totally
 independent from everyone else’s work, but it actually needs something finished