18 parts.

• LEGO Panel
• LEGO Panel 1 × 1 × 1 Corner (6231)
• LEGO Panel 1 × 2 × 1 [Rounded Corners] (4865b)
• LEGO Panel 1 × 2 × 1 [Square Corners] (4865a)
• LEGO Panel 1 × 2 × 1 with Rounded Corners and 2 Sides (23969)
• LEGO Panel 1 × 2 × 1 with Rounded Corners and Central Divider (93095)
• LEGO Panel 1 × 2 × 2 [Hollow Studs] (4864b)
• LEGO Panel 1 × 2 × 2 [Side Supports / Hollow Studs] (87552)
• LEGO Panel 1 × 2 × 3 [Hollow Studs] (2362b)
• LEGO Panel 1 × 2 × 3 [Side Supports / Hollow Studs] (87544)
• LEGO Panel 1 × 3 × 1 (23950)
• LEGO Panel 1 × 4 × 1 with Rounded Corners [Thick Wall] (43337)
• LEGO Panel 1 × 4 × 1 with Rounded Corners [Thin Wall] (15207)
• LEGO Panel 1 × 4 × 2 with Side Supports - Hollow Studs (14718)
• LEGO Panel 1 × 4 × 3 [Hollow Studs] (4215b)
• LEGO Panel 1 × 4 × 3 [Side Supports / Hollow Studs] (60581)
• LEGO Panel 1 × 6 × 5 (59349)
• LEGO Panel 2 × 2 × 1 Corner (91501)