May 16, 2021 — 200 years since the birth of Pafnuty L. Tchebyshev (1821‍—‍1894)
Plantigrade machine
Planti­grade machine
Sorting mechanism
Sort­ing mech­a­nism
Arithmometer. First model
Arith­mome­ter. First model
Wheelchair
Wheel­chair
Paddling mechanism
Pad­dling mech­a­nism
Plantigrade machine (in metal)
Planti­grade machine (in metal)
Bicycle
Bicy­cle
Arithmometer. Second model with the multiplying attachment
Arith­mome­ter. Sec­ond model with the mul­ti­ply­ing attach­ment
Adjustable arc curve ruler
Adjustable arc curve ruler
Lever-screw curvature measuring device
Lever-screw cur­va­ture mea­sur­ing device
Steam engine
Steam engine
Centrifugal governor
Cen­trifu­gal gov­er­nor
Epicyclic gear of arithmometer
Epicyclic gear of arith­mome­ter
Gear set
Gear set
Balance
Bal­ance
Parallelogram
Par­al­lel­o­gram
Press mechanism
Press mech­a­nism
Four-bar reversing approximate circle-tracing mechanism
Four-bar revers­ing approx­i­mate cir­cle-trac­ing mech­a­nism
Six-bar reversing mechanism 
Six-bar revers­ing mech­a­nism
Paradoxical mechanism
Para­dox­i­cal mech­a­nism
Two-dwell mechanism
Two-dwell mech­a­nism
One-dwell mechanism
One-dwell mech­a­nism
Long-dwell mechanism
Long-dwell mech­a­nism
Reversing and dwell mechanism
Revers­ing and dwell mech­a­nism
Multiple-bar two-dwell mechanism
Mul­ti­ple-bar two-dwell mech­a­nism
Mechanism providing two driven link oscillations per crank revolution
Mech­a­nism pro­vid­ing two dri­ven link oscil­la­tions per crank rev­o­lu­tion
Mechanism for transforming rotation into translational motion
Mech­a­nism for trans­form­ing rota­tion into trans­la­tional motion
Mechanism for transforming oscillation into rotation
Mech­a­nism for trans­form­ing oscil­la­tion into rota­tion
Circle guiding mechanism with a dwell
Cir­cle guid­ing mech­a­nism with a dwell
Mechanism with a variable lever travel
Mech­a­nism with a vari­able lever travel
Slider-crank mechanism of the steam engine
Slider-crank mech­a­nism of the steam engine
Stool
Stool
Four-bar approximate straight line mechanism
Four-bar approx­i­mate straight line mech­a­nism