## 5 Conclusions  
The theory of the mechanism of scattering of a narrow beam on complex mono- and bi-periodic microstructures with and without a transparent coating, presented in this work, indicates the potential of imparting a given microrelief to surfaces and is confirmed by modeling and research of the reflection of a helium-neon laser beam from a surface with a complex microstructure. The results of this study allow us to state that the high degree of scattering of the directed beam, achieved on complex two-periodic microstructures, makes it possible to increase the secrecy of objects, including orbital ones, as well as to eliminate glare and unmasking of hidden objects. Also, the development of this technology will help improve the adhesive properties of surfaces, which is especially important in the camouflage coating process [38].  
Femtosecond laser processing can be used to form LIPSSs on the surfaces of elements of an ordered periodic structure. The use of a femtosecond laser makes it possible to create a complex microstructure that combines micro- and nanoscale elements. It is expected that such a complexly structured surface will have the ability to effectively scatter radiation over a wide range of wavelengths.  
In the future, it is planned to improve and supplement the research by performing modeling and conducting practical experiments using a wide range of control methods, including laser interferometry [39], as well as obtaining complex microstructures in various modes of nanosecond and femtosecond laser processing.  
The study of two-periodic structures production using laser beams with variable dynamic polarization seems promising. Since this parameter has a significant effect on the spatial orientation of the elements of periodic microstructures, such technology gives a striking result [40]. The applicability of this technology to stainless steel material processing should be studied.  
Conceptualization, S.D. and I.M.G.; methodology, B.A.A. and M.K.; software, B.A.A.; validation, S.D., Y.B. and J.M.; formal analysis, I.M.G. and Y.B.; investigation, S.D., I.M.G. and M.K.; resources, B.A.A. and Y.B.; data curation, J.M.; writing--original draft preparation, S.D., Y.B., I.M.G. and M.K.; writing--review and editing, Y.B. and J.M.; visualization, B.A.A. and Y.B.; supervision, Y.B. and J.M.; project administration, S.D., M.K. and J.M.; funding acquisition, J.M. All authors have read and agreed to the published version of the manuscript.  
The authors are grateful to FCT--Fundacao para a Ciencia e Tecnologia (Portugal) who partially financially supported this work through the RD Units Project Scope: UIDP/04077/2020 and UIDB/04077/2020.  
Not applicable.  
Data Availability Statement: Data are contained within the article.  
**Acknowledgments:** The general approach has been partially developed within the research project \"Formation and transformation of periodic nanocarbon-containing structures on metal surfaces with short-pulse laser, microwave, and plasma methods\" (State reg. no. 0124U000481).  
**Conflicts of Interest:** Author [PERSON] was employed by the company \"NoviNano Lab\" LLC. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.