The OCG name, "OOPArts", is an acronym for "Out-Of-Place Artifact", a term used to describe artifacts that make no logical sense given the technology available at the time they were created. Such objects were also featured as part of the "Ancient Treasure" series in the Yu-Gi-Oh! 5D's anime. The TCG name, "Chronomaly", is a portmanteau of the word "chronology" which is the sequential order in which past events occur and "anomaly" as in an irregularity or something odd. Put together these monsters are "chronological anomalies" or "chronomalies" since these objects deviate from what would have been possible to create given the resources and technology available at that time.
Remember that you cannot use "Chronomaly Technology" and Special Summon non-"Chronomaly" monsters in the same turn.
Xyz Summon "Chronomaly Machu Mech" using the two Level 5 monsters and "Chronomaly Chateau Huyuk" using the two Level 4 monsters.
Activate the effect of "Chronomaly Chateau Huyuk", target 1 of your opponent's monsters with at least 1800 ATK. The targeted monster's ATK becomes 0.
All following calculations will be done with the assumption that that monster had exactly 1800 ATK.
Use the effect of "Chronomaly Machu Mech" on the monster that was targeted by the effect of "Chronomaly Chateau Huyuk" to inflict 1800 effect damage to your opponent. Then "Chronomaly Machu Mech" gains ATK equal to the amount of damage inflicted. This makes its total ATK 4200.
Enter the Battle Phase and attack your opponent's monster that was targeted by "Chronomaly Chateau Huyuk", then attack directly dealing a total of 6000 damage.
1800 (the first effect of "Chronomaly Machu Mech") + 4200 (the ATK of "Chronomaly Machu Mech") + 2000 (the ATK of "Chronomaly Chateau Huyuk") = 8000 damage
Each copy of "Chronomaly Pyramid Eye Tablet" gives ATK + 800 to both "Numbers", allowing the combo to work with monsters with ATK less than 1800.
Since most "Chronomaly" cards involve swarming, mass-removal cards like "Dark Hole", "Torrential Tribute" and "Deck Devastation Virus" can interdict "Chronomaly" monsters before they have a chance to infest the field with the latter-most aforementioned card perhaps being the deadliest to this Deck due to the card's lingering effect and all the non-Xyz "Chronomaly" monsters (except "Winged Sphinx") sporting 1500 or less ATK. "Light-Imprisoning Mirror" also poses a threat to their swarming and effects, as most "Chronomaly" monsters have LIGHT as their Attribute. However, "Mind Drain" can be worse in countering their Special Summoning as a lot of key Level 5 "Chronomaly" monsters (i.e. "Moai" and "Moai Carrier") are helpful in Xyz Summoning "Machu Mech".
In addition, cards like "Summon Limit", "Narrow Pass" and any cards that render Monster Card Zones useless (i.e. "Ground Collapse") can bar them from the field completely ("Summon Breaker" can also flat-out pause a spamming "Chronomaly" player's turn completely). In fact, these countermeasures, combined with anti-Special Summoning support, can almost completely shut down "Chronomaly" Decks. Finally, most "Chronomaly" monsters have scanty DEF—if "Chronomaly" Duelists go on the defensive, Defense Position-destroying card effects and piercing cards can be added boon against "Chronomaly" Decks. If you want to go on the defensive use "Giant Soldier of Steel" in your Extra Deck against burns and monsters with 1900 or more ATK.