Some quick parametrics. See how fast it is to homebrew this? I know I haven't completed a bunch of stuff but I'll get to it soon.

Base/Graphables/ParametricEquation.cs

@@ -0,0 +1,63 @@
+using Graphing.Abstract;
+using Graphing.Forms;
+using Graphing.Parts;
+using System;
+using System.Collections.Generic;
+
+namespace Graphing.Graphables;
+
+public class ParametricEquation : Graphable, ITranslatableXY
+{
+    private static int equationNum;
+
+    public double OffsetX { get; set; }
+    public double OffsetY { get; set; }
+
+    public double InitialT { get; set; }
+    public double FinalT { get; set; }
+
+    protected readonly ParametricDelegate equX, equY;
+
+    public ParametricEquation(double initialT, double finalT,
+                              ParametricDelegate equX, ParametricDelegate equY)
+    {
+        equationNum++;
+        Name = $"Parametric Equation {equationNum}";
+
+        InitialT = initialT;
+        FinalT = finalT;
+
+        this.equX = equX;
+        this.equY = equY;
+    }
+
+    public override Graphable ShallowCopy() => new ParametricEquation(InitialT, FinalT, equX, equY);
+
+    public override IEnumerable<IGraphPart> GetItemsToRender(in GraphForm graph)
+    {
+        const int step = 10;
+
+        double epsilon = Math.Abs(graph.ScreenSpaceToGraphSpace(new Int2(0, 0)).x
+                                - graph.ScreenSpaceToGraphSpace(new Int2(step / 2, 0)).x) / 5;
+        epsilon *= graph.DpiFloat / 192;
+
+        List<IGraphPart> lines = [];
+
+        Float2 previousPoint = GetPointAt(InitialT);
+        for (double t = InitialT; t <= FinalT; t += epsilon)
+        {
+            Float2 currentPoint = GetPointAt(t);
+            lines.Add(new GraphLine(previousPoint, currentPoint));
+            previousPoint = currentPoint;
+        }
+
+        return lines;
+    }
+
+    public Float2 GetPointAt(double t)
+    {
+        return new(equX(t) + OffsetX, equY(t) + OffsetY);
+    }
+}
+
+public delegate double ParametricDelegate(double t);

Testing/Program.cs

@@ -19,7 +19,8 @@ internal static class Program
         Equation equA = new(Math.Sin),
                  equB = new(Math.Cos);
         EquationDifference diff = new(2, equA, equB);
-        graph.Graph(equA, equB, diff);
+        ParametricEquation equC = new(0, 4, t => t * t - 1, t => Math.Sqrt(t) + t + 1);
+        graph.Graph(equA, equB, diff, equC);
 
         Application.Run(graph);
     }