Blazor Looping, Closures and Binding

Question

I broke this down to a simple example of Looping through some stuff but breaking it out in levels. I'm instantiating a local copy in the inner loop but that doesn't seem to work. When you try and change a value in the input it changes them all to the counter variable.

Here's the code in Blazor Fiddle https://blazorfiddle.com/s/d02wswws

@for (var i = 0; i < levels; i++)
{
    <div>Level @i</div>
    @for (var j = 0; j < stuffPerLevel; j++)            
    {
        int copy = allStuffCounter;
        <input type="text" @bind="stuff[copy]" @bind:event="oninput" />
        <div>@stuff[copy]</div>
        if(allStuffCounter < stuffCounterLimit) allStuffCounter++;
    }
}

@code
{
  string[] stuff = {"some stuff 1", ... ,"some stuff 20"};
                    
  int allStuffCounter = 0;
  int levels = 3;
  int stuffPerLevel = 4;
  int stuffCounterLimit = 11;
}