Testing stencil to prove the order that passes are rendered

TwoPassStencilShader.shader

Shader "Unlit/TwoPassStencilShader"
{
	Properties
	{
		_Color1("Colour1", Color) = (1,0,0,1)
		_Color2("Colour2", Color) = (0,0,1,1)
	}
	SubShader
	{
		Tags{ 
			"RenderType" = "Opaque" 
			"DisableBatching" = "True" //make sure it isn't combining meshes
		}

		ZTest always //make sure overlapping mesh is drawn to test the stencil behaviour

		Pass
		{

			Stencil {
				Comp always

				Pass IncrSat
			}

			CGPROGRAM
		#pragma vertex vert
		#pragma fragment frag

		#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
			};

			struct v2f
			{
				float4 vertex : SV_POSITION;
			};

			float4 _Color1;

			v2f vert(appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				return o;
			}

			fixed4 frag(v2f i) : SV_Target
			{
				return _Color1;
			}
			ENDCG
		}

		Pass
		{

			Stencil{
				Ref 2
				Comp equal
				Fail DecrSat
			}

			CGPROGRAM
		#pragma vertex vert
		#pragma fragment frag

		#include "UnityCG.cginc"

			struct appdata
			{
				float4 vertex : POSITION;
			};

			struct v2f
			{
				float4 vertex : SV_POSITION;
			};

			float4 _Color2;

			v2f vert(appdata v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				return o;
			}

			fixed4 frag(v2f i) : SV_Target
			{
				return _Color2;
			}
			ENDCG
		}
	}
}