bare/qwen3.5-9b / tier-2-l-bracket

```openscad
module lbracket() {
  // L-Bracket Dimensions
  width = 50;    // X axis
  depth_h = 40;  // Y axis (Horizontal)
  height_v = 40; // Z axis (Vertical)
  thickness = 3; // mm
  
  // Inner corner at origin (0,0,0)
  // Horizontal flange extends +Y
  // Vertical flange extends +Z
  // Thickness is centered on the inner plane
  
  union() {
    // Horizontal Flange (XY plane, thickness Z)
    // X: 0 to 50, Y: 0 to 40, Z: -1.5 to 1.5
    translate([0, 0, 0])
      cube([width, depth_h, thickness]);
    
    // Vertical Flange (XZ plane, thickness Y)
    // X: 0 to 50, Z: 0 to 40, Y: -1.5 to 1.5
    translate([0, 0, 0])
      cube([width, thickness, height_v]);
  }
  
  // Remove holes
  difference() {
    // Re-extract shape for hole positioning
    union() {
      translate([0, 0, 0])
        cube([width, depth_h, thickness]);
      translate([0, 0, 0])
        cube([width, thickness, height_v]);
    }
    
    // Hole positions
    // Horizontal Flange: X=25, Y=10, Y=30 (Centered on X-axis)
    // Vertical Flange: X=25, Z=10, Z=30 (Centered on X-axis)
    // Thickness: 3mm, Counterbore depth: 2mm
    
    // Hole parameters
    d_through = 4.5;
    d_counter = 8;
    h_counter = 2;
    
    // Horizontal Flange Holes (Axis Z)
    // Counterbore on outer side (Z=1.5 face) -> Center Z=0.5
    // Through hole centered (Z=0)
    // Y positions: 10, 30
    // X position: 25
    for (y = [10, 30]) {
      translate([25, y, 0]) {
        // Counterbore
        translate([0, 0, 0.5])
          cylinder(d = d_counter, h = h_counter, $fn=64);
        // Through Hole
        translate([0, 0, 0])
          cylinder(d = d_through, h = thickness, $fn=64);
      }
    }
    
    // Vertical Flange Holes (Axis Y)
    // Counterbore on outer side (Y=1.5 face) -> Center Y=0.5
    // Through hole centered (Y=0)
    // Z positions: 10, 30
    // X position: 25
    for (z = [10, 30]) {
      translate([25, 0, z]) {
        // Counterbore
        translate([0, 0.5, 0])
          cylinder(d = d_counter, h = h_counter, $fn=64);
        // Through Hole
        translate([0, 0, 0])
          cylinder(d = d_through, h = thickness, $fn=64);
      }
    }
  }
}

// Display
module lbracket_view() {
  // Rotate for better visualization if needed, but keeping inner corner at origin
  // lbracket();
}
```