Shader Overlay Texture

Hi,

I'm trying to learn shaders, and I'm looking to achieve the follow effect: https://youtu.be/r_w4tiHDuCg?t=81

The effect you see on the "B" and "S" where the lines scroll across the condo. I've been looking at shaders to achieve this and have this so far:

 Shader "Custom/Text"
 {
  
     Properties
     {
         // main
         _ColorMain ("Base Tint", Color) = (1,1,1,1)
         _MainTex ("Base Texture", 2D) = "white" {}
  
         // overlay
         _ColorOverlay ("Overlay Tint", Color) = (1,1,1,1)
         _OverlayTex ("Overlay Texture", 2D) = "white" {}
  
     }
  
     SubShader
     {
         Tags {
             "IgnoreProjector"="True"
             "Queue"="Transparent"
             "RenderType"="Transparent"
         }
         ZWrite Off
         Lighting Off
         Cull Off
         Fog { Mode Off }
         Blend SrcAlpha OneMinusSrcAlpha
        
         Pass
         {
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
  
             #pragma fragmentoption ARB_precision_hint_fastest
             #include "UnityCG.cginc"
  
             // variables
             fixed4 _ColorMain;
             fixed4 _ColorOverlay;
  
             sampler2D _MainTex;
             sampler2D _OverlayTex;
  
  
             // input
             struct vertexIn
             {
                 float4 vertex : POSITION;
                 float2 texcoord : TEXCOORD0;
                 float2 texcoord1 : TEXCOORD1;
             };
  
             // output
             struct vertexOut
             {
                 float4 vertex : SV_POSITION;
                 float4 texcoord01 : TEXCOORD0;
                 float4 texcoord02 : TEXCOORD1;
             };
  
             vertexOut vert(vertexIn v)
             {
                 vertexOut OUT;
                 OUT.vertex = UnityObjectToClipPos(v.vertex);
                 OUT.texcoord01.xy = v.texcoord;
                 OUT.texcoord02.xy = v.texcoord1;
                 return OUT;
             }
  
             // frag
             fixed4 frag(vertexOut IN) : SV_Target
             {
     fixed4 mainTexture = tex2D(_MainTex, IN.texcoord01.xy);
     fixed4 overlayTexture = tex2D(_OverlayTex, IN.texcoord02.xy);
     fixed4 returnTexture = mainTexture * _ColorMain;
     overlayTexture.rgb *= _ColorOverlay.rgb;
     returnTexture.rgb = overlayTexture.a * _ColorOverlay.a * (overlayTexture.rgb-returnTexture.rgb) + returnTexture.rgb;
     returnTexture.a = mainTexture.a;
     return returnTexture;
             }
  
             ENDCG
         }
     }
 }

However it's not looking anything like i'm trying to achieve, is there any insights on how to help fix this?

Thanks