Toughness: When a huge external force is applied on a metal, the metal will experience fracture. Toughness is the ability of a metal to resist fracture. The ability of a material to resist fracture due to high impact loads, is called toughness.

Strength: When external forces are applied on a metal, breaking (brittle metal) or yielding (ductile metal) may occur. Strength is the property of a metal by which it resists external force without breaking or yielding.

Stiffness: When an external force is applied on a metal, it develops an internal resistance. The internal resistance developed per unit area is called stress. Stiffness is the ability of a metal to resist deformation under stress.

Plasticity: Plasticity is the property by which a metal retains its deformation permanently, when the external force applied on it is removed.
Examples: forming, forging, hammering

It can be said that the pendulum clock is made up of invar because invar's coefficient of thermal expansion is small. So, the length of the pendulum remains unaffected during changes in temperature. Invar is derived from the word invariable. It is an alloy which is made from nickel and iron. It has a low coefficient of thermal expansion. So, there will not be linear expansion of the pendulum due to the rise in temperature. And the time shown in the clock will be accurate. Thus, invar is used in the pendulum of the clock. Invar, also known as Nickel Alloy 36, is a nickel-iron alloy noted for its uniquely low coefficient of thermal expansion. 

G00 - Move in a straight line at rapids speed.
G01 - Linear Interpolation at specified feed rate.
G02 - Circular Interpolation (Clockwise)
G03 - Circular Interpolation (Counter-Clockwise)