diff --git a/test/dofs/test_mixeddof_vararg.jl b/test/dofs/test_mixeddof_vararg.jl
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+++ b/test/dofs/test_mixeddof_vararg.jl
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+# This file is a part of JuliaFEM.
+# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE
+
+"""
+Test for variadic MixedDOF type - combining multiple DOF types at type level.
+
+This demonstrates the **vararg** approach to multi-field elements, where you
+mix DOF types together as type parameters (not with field names).
+"""
+
+using Test
+using JuliaFEM
+using JuliaFEM: Vertex, Edge, Cell, DOF, MixedDOF, create_elements!
+using Tensors
+
+@testset "🎯 MixedDOF: Variadic Multi-Field Elements" begin
+    
+    # Create minimal mesh: 2 tetrahedra sharing a face
+    # Nodes: 1-5 (vertex IDs)
+    nodes = [
+        Vec(0.0, 0.0, 0.0),  # 1
+        Vec(1.0, 0.0, 0.0),  # 2
+        Vec(0.0, 1.0, 0.0),  # 3
+        Vec(0.0, 0.0, 1.0),  # 4
+        Vec(1.0, 1.0, 1.0),  # 5
+    ]
+    
+    connectivity = [
+        (UInt32(1), UInt32(2), UInt32(3), UInt32(4)),  # Tet 1
+        (UInt32(2), UInt32(3), UInt32(4), UInt32(5)),  # Tet 2
+    ]
+    
+    mesh = Mesh{4, Tetrahedron{4}}(nodes, connectivity)
+    
+    println("\n" * "="^70)
+    println("🎯 VARIADIC MixedDOF: Type-Level Multi-Field Composition")
+    println("="^70)
+    
+    # ========================================================================
+    # Define MixedDOF with 4 fields (NO field names, just types!)
+    # ========================================================================
+    
+    println("\n📋 Defining MixedDOF (variadic, type-level)...")
+    
+    # Simple syntax - no need to repeat DOF!
+    mixed_type = @MixedDOF{
+        (Float64, Vertex),    # Field 1: Temperature at vertices
+        (Vec{3}, Vertex),     # Field 2: Displacement at vertices
+        (Float64, Cell),      # Field 3: Pressure at cells
+        (Float64, Edge)       # Field 4: Electric potential on edges
+    }
+    
+    println("   Type: $mixed_type")
+    println("   ✓ 4 DOF types mixed together")
+    println("   ✓ Access by position (tuple unpacking)")
+    println("   ✓ Simple syntax: @MixedDOF{(Float64, Vertex), (Vec{3}, Vertex), ...}")
+    
+    # ========================================================================
+    # Create elements with MixedDOF
+    # ========================================================================
+    
+    println("\n🏗️  Creating elements...")
+    
+    eltype = Element{Tetrahedron{4}, Lagrange{1}, mixed_type}
+    elements, mgr = create_elements!(mesh, eltype)
+    
+    println("   ✓ Created $(length(elements)) elements")
+    @test length(elements) == 2
+    
+    # ========================================================================
+    # Test DOF indices structure (tuple of tuples, NOT NamedTuple!)
+    # ========================================================================
+    
+    println("\n🔍 Examining DOF indices...")
+    
+    elem = first(elements)
+    println("   Element 1 DOF indices type: $(typeof(elem.dof_indices))")
+    @test elem.dof_indices isa Tuple
+    @test length(elem.dof_indices) == 4  # 4 fields
+    
+    # Unpack by position
+    T_dofs, u_dofs, p_dofs, φ_dofs = elem.dof_indices
+    
+    println("   ✓ Temperature DOFs: $T_dofs")
+    println("   ✓ Displacement DOFs: $u_dofs")
+    println("   ✓ Pressure DOFs: $p_dofs")
+    println("   ✓ Electric DOFs: $φ_dofs")
+    
+    # Validate structure
+    @test length(T_dofs) == 4   # 4 vertices
+    @test length(u_dofs) == 12  # 4 vertices × 3 components
+    @test length(p_dofs) == 1   # 1 cell (discontinuous)
+    @test length(φ_dofs) == 6   # 6 edges
+    
+    # ========================================================================
+    # Test DOF sharing between elements
+    # ========================================================================
+    
+    println("\n🔗 Testing DOF sharing...")
+    
+    elem2 = elements[2]
+    T_dofs2, u_dofs2, p_dofs2, φ_dofs2 = elem2.dof_indices
+    
+    # Vertices 2,3,4 are shared → same DOF indices
+    shared_nodes_overlap = !isempty(intersect(T_dofs, T_dofs2))
+    @test shared_nodes_overlap
+    println("   ✓ Shared vertices have same temperature DOFs")
+    
+    # Cell DOFs are unique (no sharing)
+    @test isempty(intersect(p_dofs, p_dofs2))
+    println("   ✓ Cell DOFs are unique (discontinuous)")
+    
+    # Edge DOFs: Some edges are shared
+    shared_edges_overlap = !isempty(intersect(φ_dofs, φ_dofs2))
+    @test shared_edges_overlap
+    println("   ✓ Shared edges have same electric DOFs")
+    
+    # ========================================================================
+    # Total system DOFs
+    # ========================================================================
+    
+    println("\n📊 System summary:")
+    
+    all_T_dofs = unique(vcat([collect(elem.dof_indices[1])  for elem in elements]...))
+    all_u_dofs = unique(vcat([collect(elem.dof_indices[2])  for elem in elements]...))
+    all_p_dofs = unique(vcat([collect(elem.dof_indices[3])  for elem in elements]...))
+    all_φ_dofs = unique(vcat([collect(elem.dof_indices[4])  for elem in elements]...))
+    
+    println("   Temperature DOFs: $(length(all_T_dofs)) (5 unique vertices)")
+    println("   Displacement DOFs: $(length(all_u_dofs)) (5 vertices × 3)")
+    println("   Pressure DOFs: $(length(all_p_dofs)) (2 cells, no sharing)")
+    println("   Electric DOFs: $(length(all_φ_dofs)) (9 unique edges)")
+    
+    total_dofs = length(all_T_dofs) + length(all_u_dofs) + length(all_p_dofs) + length(all_φ_dofs)
+    println("   ────────────────────────────")
+    println("   TOTAL: $total_dofs DOFs")
+    
+    @test length(all_T_dofs) == 5
+    @test length(all_u_dofs) == 15
+    @test length(all_p_dofs) == 2
+    @test length(all_φ_dofs) == 9
+    @test total_dofs == 31
+    
+    # ========================================================================
+    # Compare: MixedDOF vs NamedTuple
+    # ========================================================================
+    
+    println("\n💡 COMPARISON: MixedDOF vs NamedTuple")
+    println("   ┌─────────────────────────────────────────────────────────┐")
+    println("   │ MixedDOF (vararg):                                      │")
+    println("   │   - Type-level composition                              │")
+    println("   │   - Access by position: T_dofs, u_dofs, ... = elem.dof_indices │")
+    println("   │   - More compact type signature                         │")
+    println("   │                                                         │")
+    println("   │ NamedTuple:                                             │")
+    println("   │   - Named fields                                        │")
+    println("   │   - Access by name: elem.dof_indices.T, .u, .p, .φ    │")
+    println("   │   - More readable, self-documenting                     │")
+    println("   │                                                         │")
+    println("   │ BOTH ARE SUPPORTED! Choose based on preference.        │")
+    println("   └─────────────────────────────────────────────────────────┘")
+    
+    println("\n" * "="^70)
+    println("✅ ALL TESTS PASSED: Variadic MixedDOF works!")
+    println("="^70)
+end