diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 82c23f02..d5fcdb2d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -55,6 +55,8 @@ jobs:
         env:
           PYTHON: ""
       - uses: julia-actions/julia-processcoverage@v1
+        with:
+          directories: src,examples,ext
       - uses: coverallsapp/github-action@master
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/Project.toml b/Project.toml
index f49f5b63..bd5a5c1c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -7,7 +7,17 @@ version = "0.2.4-pre"
 HOHQMesh_jll = "1d5cbd98-5122-5a8a-bea1-c186d986ee7f"
 Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 
+[weakdeps]
+Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"
+
+[extensions]
+HOHQMeshMakieExt = "Makie"
+
 [compat]
 HOHQMesh_jll = "1.0"
+Makie = "0.20"
 Requires = "1.1.3"
 julia = "1.6"
+
+[extras]
+Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"
diff --git a/ext/HOHQMeshMakieExt.jl b/ext/HOHQMeshMakieExt.jl
new file mode 100644
index 00000000..d42597ec
--- /dev/null
+++ b/ext/HOHQMeshMakieExt.jl
@@ -0,0 +1,24 @@
+# Package extension for adding Makie-based features to HOHQMesh.jl
+module HOHQMeshMakieExt
+
+# Required for visualization code
+if isdefined(Base, :get_extension)
+    using Makie
+else
+    # Until Julia v1.9 is the minimum required version for HOHQMesh.jl, we still support Requires.jl
+    using ..Makie
+end
+
+# Use all exported symbols to avoid having to rewrite all the visualization routines
+using HOHQMesh
+
+# Use additional symbols that are not exported
+using HOHQMesh: Project, hasBackgroundGrid, projectBounds, projectGrid
+
+# Import functions such that they can be extended with new methods
+import HOHQMesh: plotProject!, updatePlot!
+
+include("VizMesh.jl")
+include("VizProject.jl")
+
+end
\ No newline at end of file
diff --git a/src/Viz/VizMesh.jl b/ext/VizMesh.jl
similarity index 100%
rename from src/Viz/VizMesh.jl
rename to ext/VizMesh.jl
diff --git a/src/Viz/VizProject.jl b/ext/VizProject.jl
similarity index 84%
rename from src/Viz/VizProject.jl
rename to ext/VizProject.jl
index 718a4ffa..6b2550c8 100644
--- a/src/Viz/VizProject.jl
+++ b/ext/VizProject.jl
@@ -1,21 +1,4 @@
 
-const MODEL = 1; const GRID = 2; const MESH = 4; const EMPTY = 0
-const REFINEMENTS = 8; const ALL = 15
-
-
-"""
-    plotProject!(proj::Project, plotOptions::Int = 0)
-
-Plot objects specified by the `plotOptions`. Construct the `plotOptions` by the sum
-of what is to be drawn from the choices `MODEL`, `GRID`, `MESH`, `REFINEMENTS`.
-
-Example: To plot the model and the grid, `plotOptions = MODEL + GRID`. To plot
-just the mesh, `plotOptions = MESH`.
-
-To plot everything, `plotOptions = MODEL + GRID + MESH + REFINEMENTS`
-
-Contents are overlaid in the order: GRID, MESH, MODEL, REFINEMENTS
-"""
 function plotProject!(proj::Project, plotOptions::Int = 0)
 
     if isnothing(proj.plt)
@@ -113,11 +96,8 @@ function plotProject!(proj::Project, plotOptions::Int = 0)
 end
 
 
-"""
-    updatePlot!(proj::Project)
-
-This version replots the figure with the current options. Legacy.
-"""
+#     updatePlot!(proj::Project)
+# This version replots the figure with the current options. Legacy.
 function updatePlot!(proj::Project)
     if !isnothing(proj.plt)
         proj.plt = Figure(size = (1000, 1000))
@@ -127,15 +107,6 @@ function updatePlot!(proj::Project)
 end
 
 
-"""
-    updatePlot!(proj::Project, plotOptions::Int)
-
-Replot with the new plotOptions = combinations (sums) of
-
-    GRID, MESH, MODEL, REFINEMENTS
-
-Example: updatePlot!(p, MESH + MODEL)
-"""
 function updatePlot!(proj::Project, plotOptions::Int)
     if !isnothing(proj.plt)
         proj.plt = Figure(size = (1000, 1000))
diff --git a/src/HOHQMesh.jl b/src/HOHQMesh.jl
index 312d4421..2a529a71 100644
--- a/src/HOHQMesh.jl
+++ b/src/HOHQMesh.jl
@@ -7,25 +7,19 @@ using HOHQMesh_jll: HOHQMesh_jll
 using Requires: @require
 
 function __init__()
-  # Enable features that depend on the availability of the Makie package
-  @require Makie="ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a" begin
-    using .Makie
-    if isdefined(Makie, :to_textsize)
-      @warn "You seem to be using an older version of Makie (< v0.19). Some plotting functions may not work."
+    # Enable features that depend on the availability of the Makie package
+    # Until Julia v1.9 is the minimum required version for HOHQMesh.jl, we still support Requires.jl
+    @static if !isdefined(Base, :get_extension)
+        @require Makie="ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a" begin
+            include("../ext/HOHQMeshMakieExt.jl")
+        end
     end
-    include("Viz/VizProject.jl")
-    include("Viz/VizMesh.jl")
-    # Make the actual plotting routines available
-    export plotProject!, updatePlot!
-    # Make plotting constants available for easier use
-    export MODEL, GRID, MESH, EMPTY, REFINEMENTS, ALL
-  end
 end
 
 #
 # Include interactive mesh functionality for creating, reading, and writing a model for HOHQMesh.
-# Note, The visualization routines are included above in the `__init__` because
-# Makie is required.
+# Note, Empty visualization routines are included and exported below but are extended within
+# `../ext/HOHQMeshMakieExt.jl`
 #
 
 # Core interactive tool routines for control file readin, curve evaluation, etc.
@@ -53,6 +47,9 @@ include("Project/SmootherAPI.jl")
 # Main routine that uses HOHQMesh to generate a mesh from an interactive `Project`
 include("Mesh/Meshing.jl")
 
+# Empty routines for visualization extended in `ext/HOHQMeshMakieExt.jl`
+include("Viz/visualization.jl")
+
 # Generic main function to generate a mesh from a control file
 # or an interactive mesh `Project`
 export generate_mesh
@@ -149,6 +146,9 @@ export undo, undoActionName,
 # Functions from `Meshing.jl`, generate_mesh is already exported
 export remove_mesh!
 
+# Functions and constants for visualization purposes
+export plotProject!, updatePlot!
+export MODEL, GRID, MESH, EMPTY, REFINEMENTS, ALL
 
 """
     generate_mesh(control_file;
diff --git a/src/Viz/visualization.jl b/src/Viz/visualization.jl
new file mode 100644
index 00000000..9a0081e5
--- /dev/null
+++ b/src/Viz/visualization.jl
@@ -0,0 +1,45 @@
+
+# Convenience constants to make plotting easier
+const MODEL = 1; const GRID = 2; const MESH = 4; const EMPTY = 0
+const REFINEMENTS = 8; const ALL = 15
+
+# Add function definitions here such that they can be exported from HOHQMesh.jl
+# and extended in the HOHQMeshMakieExt package extension or by the
+# Makie-specific code loaded by Requires.jl
+
+"""
+    plotProject!(proj::Project, plotOptions::Int = 0)
+
+Plot objects specified by the `plotOptions`. Construct the `plotOptions` by the sum
+of what is to be drawn from the choices `MODEL`, `GRID`, `MESH`, `REFINEMENTS`.
+
+Example: To plot the model and the grid, `plotOptions = MODEL + GRID`. To plot
+just the mesh, `plotOptions = MESH`.
+
+To plot everything, `plotOptions = MODEL + GRID + MESH + REFINEMENTS`
+
+Contents are overlaid in the order: `GRID`, `MESH`, `MODEL`, `REFINEMENTS`
+
+!!! note "Requires Makie.jl"
+    Please note that for this function to work, you need to load Makie.jl
+    in your REPL (e.g., by calling `using GLMakie`).
+"""
+function plotProject! end
+# Note: The function implementation is found in `ext/VizProject.jl`.
+
+
+"""
+    updatePlot!(proj::Project, plotOptions::Int)
+
+Replot with the new plotOptions = combinations (sums) of
+
+    GRID, MESH, MODEL, REFINEMENTS
+
+Example: `updatePlot!(p, MESH + MODEL)`
+
+!!! note "Requires Makie.jl"
+    Please note that for this function to work, you need to load Makie.jl
+    in your REPL (e.g., by calling `using GLMakie`).
+"""
+function updatePlot! end
+# Note: The function implementation is found in `ext/VizProject.jl`.
\ No newline at end of file