round is part of:
    80%  circular
    50%  cylindrical

round contains:
    90%  disc
    80%  cylindrical
    72%  half-cylindrical  (indirectly)
    40%  hub
    40%  tire

Full expansion for round:
   100%  Rubber Belt from 1782
   100%  Rubber Belt from 1822
   100%  Rubber Belt from 5561
   100%  Rubber Belt from 5988
   100%  Rubber Belt from 8213
   100%  Rubber Belt from 8226
   100%  Rubber Belt from 8232
   100%  Technic Rubber Belt
   100%  1x1 Round Plate
   100%  2x2 Disc w/ Convex Round Bottom
   100%  2x2 Radar Dish
   100%  2x2 Round Plate
   100%  2x2 Round Plate / Barrel Lid
   100%  2x2 Round Tile
   100%  2x2 Round Tile w/ Analog Clock
   100%  2x2 Round Tile w/ Criss-Cross Lines
   100%  2x2 Round Tile w/ Pizza
   100%  2x2 Round Tile w/ Submarine
   100%  2x2 Round Tile w/ Zebra Skin
   100%  2x2x2 Round Space Landing Pad
   100%  4x4 Radar Dish
   100%  4x4 Swirl-Pattern Radar Dish
   100%  4x4 Umbrella/Radar Dish
   100%  6x6 Webbed Radar Dish
   100%  8x8 Radar Dish
   100%  8x8 Round Tile w/ 4 Center Studs
    95%  1x1 Coin w/ Sprue (0 sets)
    95%  1x1x.5 Technic Pulley w/ Toothing
    95%  1x1x.5 Toothless Technic Pulley
    95%  3x3 Technic Pulley
    90%  3x3 Technic Wheel Hub/Tri-Pulley
    90%  3x3 Thin-Disc w/ Center Axle-Hole
    80%  Cylindrical Technic Piston Head
    80%  1.5x1.5 12-Tooth Technic Bevel Gear
    80%  1.5x1.5 Micro-Motor-Style Pulley
    80%  1x1 8-Tooth Technic Gear
    80%  1x1 Cylinder Brick
    80%  1x1 PRIMO Cylinder Brick w/ Bee
    80%  1x1 PRIMO Cylinder Brick w/ Flowers
    80%  1x1 PRIMO Cylinder Brick w/ Frog
    80%  1x1 PRIMO Cylinder Brick w/ Ladybug
    80%  1x1 PRIMO Cylinder Brick w/ Penguin
    80%  1x1 PRIMO Cylinder Brick w/ Polar-Bear
    80%  1x1 PRIMO Cylinder Brick w/ Smile
    80%  1x1x.6 Rounded Light Cap
    80%  1x1x2 Cylinder Brick
    80%  2L Cylinder w/ Dual End Peg Holes
    80%  2x2 16-Tooth Technic Gear
    80%  2x2 Cyl.Brick w/ BlackBox, 2x4 Gray Dots
    80%  2x2 Cylinder Brick
    80%  2x2x2 Barrel w/ Lid
    80%  2x2x2 Lidless Barrel
    80%  3x3 24-Tooth Technic Crown Gear
    80%  3x3 24-Tooth Technic Gear
    80%  4x4 40-Tooth Technic Gear
    80%  4x4 Dome-Backing Disc w/ 1x2 Plate
    80%  4x4x1.6 Hex-Pattern Dome
    80%  4x4x2 Cylinder Hub w/ 6 Peg Holes
    80%  4x4x3.5 Lidless Barrel
    72%  Large Tiny-Peg Hub
    72%  Large Tiny-Peg Hub w/ Treaded Tires
    72%  Small Tiny-Peg Hub
    72%  Small Tiny-Peg Hub w/ Treaded Tires
    72%  Small Tiny-Peg Hub w/ WideFlat Tires
    72%  2x2 FreeStyle Hub w/ Large Tires
    72%  2x2 FreeStyle Hub w/ Small Tires
    72%  2x2 Spoked Hub w/ Treaded Tires
    72%  2x2 Studded Hub w/ Metal Peg
    72%  2x2 Studded Hub w/ Peg Hole
    72%  2x2 Technic Cross-Axle Hub
    72%  2x2 Technic Cross-Axle Hub w/Lg.Tires
    72%  2x2 Technic Cross-Axle Hub w/Sm.Tires
    72%  2x4x4 Half-Cylinder
    72%  4x4x1 Cylinder Brick w/ 4 Peg Holes
    70%  2x2 Round Plate w/ Bottom Pulley
    70%  2x2 Round Plate w/ Cart-Wheels
    68%  Small Tiny-Peg Hub w/ Thin Tires
    64%  2x2 Elbow-Bend Cylinder
    64%  2x2x11 Cylinder Brick w/ Sq. Base
    64%  3x3 Technic Pulley w/ Tires
    64%  4x4x1.3 Grooved Hub w/ 7 Peg Holes
    64%  4x4x1.6 Grooved Hub w/ 7 Peg Holes
    60%  2x2x2 Cylinder Brick w/ 4 Fins
    56%  1x1x1 Cylinder Brick w/ 4 Fins
    50%  Hand-Held Round Paddle
    50%  2x2 Round Tile w/ Top Hook Hole
    50%  2x2x2 Spherical Crystal Ball
    50%  2x2x2 Trash Can w/ Lid
    50%  2x2x2 Trash Can, No Lid
    50%  4x4 Round Tree Stump
    50%  6x6 Octagonal Umbrella
    48%  2x2x1.6 Bell-Jar
    40%  "30.4x14 VR" Tire, no hubs
    40%  Large Tire for 2x2 Hub
    40%  Large Treaded Tiny-Peg Tire
    40%  Small Smooth Tires from 6444, no hubs
    40%  Small Tire for 2x2 Hub
    40%  Small Treaded Tiny-Peg Tire
    40%  1x1x4 Round Antenna
    40%  1x1x8 Super-Tall Antenna
    40%  2x2 Quarter-Circle Brick
    40%  3x3 Rubber Tire for Technic Pulley
    40%  4x4 Brick Turntable
    32%  2x2 Plate w/ Metal Axle & Lg Tires
    32%  2x2 Plate w/ Metal Axle & Sm Tires
    32%  2x2 Plate w/ Tiny Gray Wheels
    32%  2x4 Brick w/ Red 2x2-Stud End Hubs
    32%  3x3 Technic Hub w/ "30.4x14 VR" Tire
    32%  3x3x2 10+10-Tooth Tank-Tread Hub
    32%  4x4 Technic Hub w/ "13x24" Tire
    32%  4x4 Technic Hub w/ "43.2x28 S" Tire
    32%  4x7 Car Chassis w/ Tires & Hubs
    32%  5x5 Technic Hub w/ "20x30" Tire
    32%  5x5 Technic Hub w/ "49.6x28 VR" Tire
    32%  5x5 Technic Hub w/ "68.8x40 Q" Tire
    24%  Laser-Gun, Cyl. Nozzle
    24%  2x2x4 Cone/Cylinder Jet Engine Shell
    16%  12x12 Quarter-Disc Brick
    16%  4x4 Quarter-Disc Brick
    10%  1x1 Spigot
     8%  1x1 Cyl. Brick w/ 5-Stripe LEGO Flag
     8%  1x1 Cyl. Brick w/ Pole & Plain Flag
     8%  2x2 Cylinder Brick w/ 6 Fan Blades
     5%  3x4x3 Sloped Wall w/ Round Window
     4%  12x24 Sunken Dual-Quarter-Disc Brick
     4%  24x24 Brick Minus Quarter-Disc